Your network contains an Active Directory domain. The domain contains several domain controllers.
All domain controllers run Windows Server 2008 R2.
You need to restore the Default Domain Controllers Policy Group Policy object (GPO) to the Windows Server
2008 R2 default settings.
What should you do?

A.
Run dcgpofix.exe /target:dc.

B.
Run dcgpofix.exe /target:domain.

C.
Delete the link for the Default Domain Controllers Policy, and then run gpupdate.exe /sync.

D.
Delete the link for the Default Domain Controllers Policy, and then run gpupdate.exe /force.

Explanation:
Reference:
http://technet.microsoft.com/en-us/library/hh875588.aspx
Dcgpofix
Recreates the default Group Policy Objects (GPOs) for a domain.
Syntax
DCGPOFix [/ignoreschema] [/target: {Domain | DC | Both}] [/?]
/ignoreschema
Ignores the version of the Active Directory schemawhen you run this command. Otherwise, the command
only works on the same schema version as the Windows version in which the command was shipped.
/target {Domain | DC | Both}
Specifies which GPO to restore. You can restore theDefault Domain Policy GPO, the Default Domain
Controllers GPO, or both.
Examples
Restore the Default Domain Controllers Policy GPOto its original state. You will lose any changes that you
have made to this GPO.
dcgpofix /ignoreschema /target:DC