You need to design a Windows Server Update Services (WSUS) infrastructure that meets the following requirements:

The updates must be distributed from a central location.

All computers must continue to receive updates in the event that a server fails.

What should you include in your design?

A.
Configure two WSUS servers in a Microsoft SQL Server 2008 failover cluster. Configure each WSUS server to use a local database.

B.
Configure a single WSUS server to use multiple downstream servers. Configure each WSUS server to use a RAID 1 mirror and a local database.

C.
Configure a single WSUS server to use multiple downstream servers. Configure each WSUS server to use a RAID 5 array and a local database.

D.
Configure a Microsoft SQL Server 2008 failover cluster. Configure two WSUS servers in a Network Load Balancing cluster. Configure WSUS to use the remote SQL Server 2008 database instance.

Explanation:

http://technet.microsoft.com/en-us/library/dd939812(v=WS.10).aspx

WSUS database
WSUS 3.0 SP2 requires a database for each WSUS server. WSUS supports the use of a database that resides on a different computer than the WSUS server, with some restrictions. For a list of supported databases and remote database limitations, see WSUS database requirements.
The WSUS database stores the following information:
WSUS server configuration information
Metadata that describes each update
Information about client computers, updates, and interactions

If you install multiple WSUS servers, you must maintain a separate database for each WSUS server, whether it is an autonomous or a replica server. (For more information about WSUS server types, see Design the WSUS Server Layout.) You cannot store multiple WSUS databases on a single instance of SQL Server, except in Network Load Balancing (NLB) clusters that use SQL Server failover. For more about this configuration, see Configure WSUS for Network Load Balancing.

SQL Server, SQL Server Express, and Windows Internal Database provide the same performance characteristics for a single server configuration, where the database and the WSUS service are located on the same computer. A single server configuration can support several thousand WSUS client computers.

Windows Server 2008 Enterprise Edition

Windows Server 2008 Enterprise Edition is the version of the operating system targeted at large businesses. Plan to deploy this version of Windows 2008 on servers that will run applications such as SQL Server 2008 Enterprise Edition and Exchange Server 2007. These products require the extra processing power and RAM that Enterprise Edition supports. When planning deployments, consider Windows Server 2008 Enterprise Edition in situations that require the following technologies unavailable in Windows Server 2008 Standard Edition:

Failover ClusteringFailover clustering is a technology that allows another server to continue to service client requests in the event that the original server fails. Clustering is covered in more detail in Chapter 11, Clustering and High Availability. You deploy failover clustering on mission-critical servers to ensure that important resources are available even if a server hosting those resources fails.