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 the new server， run dcpromo /adv.
• B、On the new server， run dcpromo /createdcaccount.
• C、On a domain controller run adprep /rodcprep.
• D、On a domain controller， run adprep /forestprep.