Your network contains an Active Directory domain named contoso.com. The domain
contains five domain controllers.
You add a logoff script to an existing Group Policy object (GPO).
You need to verify that each domain controller successfully replicates the updated group
policy.
Which two objects should you verify on each domain controller? (Each correct answer
presents part of the solution. Choose two.)

A.
\\servername\SYSVOL\contoso.com\Policies\{GUID}\gpt.ini

B.
\\servername\SYSVOL\contoso.com\Policies\{GUID}\machine\registry.pol

C.
the uSNChanged value for the
CN={GUID},CN=Policies,CN=System,DC=contoso,DC=com container

D.
the versionNumber value for the
CN={GUID},CN=Policies,CN=System,DC=contoso,DC=com container

Explanation:
http://technet.microsoft.com/en-us/library/cc784268%28v=ws.10%29.aspx
How Core Group Policy Works
…
The Gpt.ini File
The Gpt.ini file is located at the root of each Group Policy template. Each Gpt.ini file contains
GPO version information. Except for the Gpt.ini files created for the default GPOs, a display
name value is also written to the file.
Each Gpt.ini file contains the GPO version number of the Group Policy template.
[General]
Version=65539
Normally, this is identical to the version-number property of the corresponding
GroupPolicyContainer object. It is encoded in the same way — as a decimal representation
of a 4 byte hexadecimal number, the upper two bytes of which contain the GPO user
settings version and the lower two bytes contain the computer settings version. In this
example the version is equal to 10003 hexadecimal giving a user settings version of 1 and a
computer settings version of 3.
Storing this version number in the Gpt.ini allows the CSEs to check if the client is out of date
to the last processing of policy settings or if the currently applied policy settings (cached
policies) are up-to-date. If the cached version is different from the version in the Group
Policy template or Group Policy container, then policy settings will be reprocessed.