What should you do first?

Your company has a single Active Directory domain.
All domain controllers run Windows Server 2003.
You install Windows Server 2008 R2 on a server.
You need to add the new server as a domain controller in your domain.
What should you do first?
A. On a domain controller run adprep /rodcprep.
B. On the new server, run dcpromo /adv.
C. On the new server, run dcpromo /createdcaccount.
D. On a domain controller, run adprep /forestprep.