Your network contains an Active Directory forest. The forest contains a single domain named contoso.com and
corp.contoso.com. The forest contains four domain controllers.
The domain controllers are configured as shown in the following table.

All domain controllers are DNS servers.
In the corp.contoso.com domain, you plan to deploy a new domain controller named DC5.
You need to identify which domain controller must be online to ensure that DC5 can be promoted successfully
to a domain controller.
Which domain controller identify which domain controller must be online to ensure that DC5 can be promoted
successfully to a domain controller.
Which domain controller should you identify?

A.
DC1

B.
DC2

C.
DC3

D.
DC4

Explanation:
In order to add a Domain Controller to corp.contoso.com, you need PDC and RID of that domain, not of the root
domain. The Domain Naming Master is needed to add, remove and rename domains in the forest, i.e. not for
individual Domain Controllers.