Your network contains an Active Directory forest.
The forest contains two domains named contoso.com and fabrikam.com.
The functional level of the forest is Windows Server 2003.
The contoso.com domain contains domain controllers that run either Windows Server 2008 or Windows Server 2008 R2.
The functional level of the domain is Windows Server 2008.
The fabrikam.com domain contains domain controllers that run either Windows Server 2003 or Windows Server 2008.
The functional level of the domain is Windows Server 2003.
The contoso.com domain contains a member server named Server1 that runs Windows Server 2012 R2.
You install the Active Directory Domain Services server role on Server1.
You need to add Server1 as a new domain controller in the contoso.com domain.
What should you do?

A.
Run the Active Directory Domain Services Configuration Wizard.

B.
Run adprep.exe /domainprep, and then run dcpromo.exe.

C.
Raise the functional level of the forest, and then run dcprorno.exe.

D.
Modify the Computer Name/Domain Changes properties.

Explanation:
Windows Server 2012 R2 requires a Windows Server 2003 forest functional level.
That is, before you can add a domain controller that runs Windows Server 2012 R2 to an existing Active Directory forest, the forest functional level must be
Windows Server 2003 or higher.
http://blogs.technet.com/b/askpfeplat/archive/2012/09/03/introducing-the-first-windowsserver-2012-domaincontroller.aspx
http://technet.microsoft.com/en-us/library/dd464018(v=ws.10).aspx
http://technet.microsoft.com/en-us/library/jj574134.aspx