You need to deploy a read-only domain controller (RODC) that runs Windows Server 2008
R2.
What is the minimal forest functional level that you should use?
A.
Windows Server 2008 R2
B.
Windows Server 2008
C.
Windows Server 2003
D.
Windows 2000
Explanation:
http://technet.microsoft.com/en-us/library/cc731243.aspx
Prerequisites for Deploying an RODC
Complete the following prerequisites before you deploy a read-only domain controller
(RODC):
Ensure that the forest functional level is Windows Server 2003 or higher, so that linkedvaluereplication (LVR) is available.