Your network contains an Active Directory forest named contoso.com.
The contoso.com domain only contains domain controllers that run Windows Server 2012 R2.
The forest contains a child domain named child.contoso.com.
The child.contoso.com domain only contains domain controllers that run Windows Server 2008 R2.
The child.contoso.com domain contains a member server named Server1 that runs Windows
Server 2012 R2.
You have access to four administrative user accounts in the forest.
The administrative user accounts are configured as shown in the following table.

You need to ensure that you can add a domain controller that runs Windows Server 2012 R2 to the
child.contoso.com domain.
Which account should you use to run adprep.exe?

A.
Admin1

B.
Admin2

C.
Admin3

D.
Admin4

Explanation:
http://technet.microsoft.com/en-us/library/dd464018(v=ws.10).aspx