Your network contains a single Active Directory domain.
You plan to deploy System Center 2012 Configuration Manager.
The hierarchy will have a Central Administration Site and five Primary Sites.
You need to ensure that you can target user groups for software distribution.
The solution must minimize network traffic.
Which Configuration Manager discovery method should you use?

A.
Active Directory User Discovery and Active Directory Group Discovery on the primary sites

B.
Active Directory User Discovery and Active Directory Group Discovery on the Central
Administration site

C.
Active Directory User Discovery on the Central Administration site and Active Directory Group
Discovery on the primary sites

D.
Active Directory User Discovery on the primary sites and Active Directory Group Discovery on
every site

Explanation:
http://technet.microsoft.com/en-us/library/gg712681.aspx#BKMK_ChooseCAS
Determine Whether to Install a Central Administration Site
Install a central administration site if you plan to install multiple primary sites. Use a central
administration site to configure hierarchy-wide settings and to monitor all sites and objects in the
hierarchy. This site type does not manage clients directly but it does coordinate inter-site data
replication, which includes the configuration of sites and clients throughout the hierarchy.
Use the following information to help you plan for a central administration site:

..
You can manage all clients in the hierarchy and perform site management tasks for any primary site
when you use a Configuration Manager console that is connected to the central administration site.
..
You can configure discovery operations throughout the hierarchy from the central administration
site by assigning discovery methods to run at individual sites.
http://technet.microsoft.com/en-us/library/gg712308.aspx
Planning for Discovery in Configuration Manager
System Center 2012 Configuration Manager discovery identifies computer and user resources that
you can manage by using Configuration Manager. It can also discover the network infrastructure in
your environment.
Discovery Methods in Configuration Manager
Before you enable discovery methods for Configuration Manager, ensure you understand what each
method can discover. Because discovery can generate a large volume of network traffic, and the
resultant DDRs can result in a significant use of CPU resources during processing, plan to use only
those discovery methods that you require to meet your goals. You could use only one or two
discovery methods to be successful, and you can always enable additional methods in a controlled
manner to extend the level of discovery in your environment.
..
Active Directory User Discovery
Discovers user accounts from the specified locations in Active Directory Domain Services.
Active Directory Group Discovery Discovers local, global, and universal security groups, the
membership within these groups, and the membership within distribution groups from the specified
locations in Active directory Domain Services.
Distribution groups are not discovered as group resources.
..
About Discovery Data Records
Discovery data records (DDRs) are files created by a discovery method that contain information
about a resource you can manage in Configuration Manager. DDRs contain information about
computers, users and in some cases, network infrastructure. They are processed at primary sites or
at central administration sites. After the resource information in the DDR is entered into the
database, the DDR is deleted and the information replicates as global data to all sites in the
hierarchy.
The site at which a DDR is processed depends on the information it contains:
DDRs for newly discovered resources that are not in the database are processed at the top-level site
of the hierarchy. The top-level site creates a new resource record in the database and assigns it a
unique identifier. DDRs transfer by file-based replication until they reach the top-level site.
DDRs for previously discovered objects are processed at primary sites. Child primary sites do not
transfer DDRs to the central administration site when the DDR contains information about a
resource that is already in the database.
Secondary site do not process discovery data records and always transfer them by file-based
replication to their parent primary site.
DDR files are identified by the .ddr extension, and have a typical size of about 1 KB.
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Decide Which Discovery Methods to Use
Discover Users
When you want to discover information about users, you can use Active Directory User Discovery.
Similar to

Active Directory System Discovery, this method discovers users from Active Directory and includes
basic information in addition to extended Active Directory information. You can use this information
to build complex queries and collections similar to those for computers.
Discover Group Information
When you want to discover information about groups and group memberships, use Active Directory
Group Discovery. This discovery method creates resource records for security groups.
You can use this method to search a specific Active Directory group to identify the members of that
group in addition to any nested groups within that group. You can also use this method to search an
Active Directory location for groups, and recursively search each child container of that location in
Active Directory Domain Services.
This discovery method can also search the membership of distribution groups. This can identify the
group relationships of both users and computers.
When you discover a group, you can also discover limited information about its members. This does
not replace Active Directory System or User Discovery and is usually insufficient to build complex
queries and collections or serve as the bases of a client push installation.
Decide Where to Run Discovery
When you plan to use discovery in Configuration Manager, you must consider where to run each
discovery method.
After Configuration Manager adds discovery data to a database, it is quickly shared between all sites
in the hierarchy. Because there is no benefit to discovering the same information at multiple sites in
your hierarchy, consider configuring a single instance of each discovery method that you use to run
at a single site instead of running multiple instances of a single method at different sites.

Further information:
Best Practices for Discovery
Run Active Directory System Discovery and Active Directory User Discovery before you run Active
Directory
Group Discovery
When Active Directory Group Discovery identifies a previously undiscovered user or computer as a
member of a group, it attempts to discover basic details for the user or computer. Because Active
Directory Group
Discovery is not optimized for this type of discovery, this process can cause Active Directory Group
Discovery to run slow. Additionally, Active Directory Group Discovery identifies only the basic details
about users and computers is discovers, and does not create a complete user or computer discovery
record. When you run Active Directory System Discovery and Active Directory User Discovery, the
additional Active Directory attributes for each object type are available, and as a result, Active
Directory Group Discovery runs more efficiently.
When you configure Active Directory Group Discovery, only specify groups that you use with
Configuration Manager

To help control the use of resources by Active Directory Group Discovery, specify only those groups
that you use with Configuration Manager. This is because Active Directory Group Discovery
recursively searches each group it discovers for users, computers, and nested groups. The search of
each nested group can expand the scope of Active Directory Group Discovery and reduce
performance. Additionally, when you configure delta discovery for Active Directory Group Discovery,
the discovery method monitors each group for changes. This further reduces performance when the
method must search unnecessary groups.
Run Active Directory Discovery methods at primary site that has a network location that is closest to
your Active Directory domain controller.
To improve the performance of Active Directory discovery, it is recommended to run discover at a
primary site that has a fast network connection to your domain controllers. If you run the same
Active Directory discovery method at multiple sites, it is recommended to configure each discovery
method to avoid overlap. Unlike past versions of Configuration Manager, discovery data is shared
between sites. Therefore, it is not necessary to discovery the same information at multiple sites.
http://configmgrblog.com/2011/12/29/discovery-methods-in-configuration-manager-2012/
Discovery Methods in Configuration Manager 2012
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Active Directory User Discovery can be configured on Central Administration Sites and Primary Sites.
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Active Directory Group Discovery can be configured on Central Administration Sites and Primary
Sites.