You work as the network administrator at ABC.com. The ABC.com network has a domain named ABC.com. All servers on the ABC.com network have Windows Server 2008 R2 installed

All master roles in the forest are maintained at a domain controller ABC-DC01. You have another domain controller in the network named ABC-DC02 which contains better hardware and can improve performance. ABC-DC01 is to be removed from the network.

Which option can you select in order to ensure that proper roles are transferred to ABC-DC02 without disrupting the forest wide operations?

A.
You should consider transferring the RID Master role and the Schema master role.

B.
You should consider transferring the Schema master role and the Domain naming master role.

C.
You should consider transferring the Infrastructure master role and the PDC emulator role.

D.
You should consider transferring the Infrastructure master role and the Domain naming master role.

E.
You should consider transferring the RID Master role and the PDC emulator role.

Explanation:
In order to transfer all forest-wide operation master roles to another domain you need to transfer Domain naming master as well as the Schema master. Schema Master: The schema master domain controller controls all updates and modifications to the schema. To update the schema of a forest, you must have access to the schema master. There can be only one schema master in the whole forest. Domain naming master: The domain naming master domain controller controls the addition or removal of domains in the forest. There can be only one domain naming master in the whole forest.

Reference: http://support.microsoft.com/kb/324801