Your network contains an Active Directory domain named contoso.com. The Active Directory
site topology is configured as shown in the exhibit. (Click the Exhibit button.)

DC1 and DC2 run Windows Server 2003 R2. All FSMO roles are located on DC2.
You plan to deploy a read-only domain controller (RODC) to Site3.
You need to recommend changes to the network to support the planned RODC
implementation.
What should you recommend?
More than one answer choice may achieve the goal. Select the BEST answer.

A.
To Site1, add an RODC that runs Windows Server 2012.

B.
Replace DC2 with a domain controller that runs Windows Server 2012.

C.
To Site2, add an RODC that runs Windows Server 2012.

D.
Replace DC1 with a domain controller that runs Windows Server 2012.

Explanation:
http://technet.microsoft.com/en-us/library/cc772065%28v=ws.10%29.aspx
Each RODC requires a writable domain controller running Windows Server 2008 for the
same domain from which the RODC can directly replicate.
Typically, this requires that a writable domain controller running Windows Server 2008 be
placed in the nearest site in the topology.