Which domain controller should you identify?

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

All domain controllers are DNS servers.
You plan to deploy a new domain controller named DC5 in the contoso.com domain.
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 should you identify?

A.
DC1

B.
DC2

C.
DC3

D.
DC4