Your network contains an Active Directory domain. The domain contains a member server named Server1 that
runs Windows Server 2008 R2.
You need to configure Server1 as a global catalog server.
What should you do?

A.
Modify the Active Directory schema.

B.
From Ntdsutil, use the Roles option.

C.
Run the Active Directory Domain Services Installation Wizard on Server1.

D.
Move the Server1 computer object to the Domain Controllers organizational unit (OU).

Explanation:
Now it’s just a member server, so you’ll have to run dcpromo to start the Active Directory Domain Services
Installation Wizard in order to promote the server to a domain controller. Only a domain controller can be a
global catalog server.
Reference:
http://technet.microsoft.com/en-us/library/cc728188.aspx
The global catalog is a distributed data repositorythat contains a searchable, partial representationof every
object in every domain in a multidomain Active Directory Domain Services (AD DS) forest. The global catalog is
stored on domain controllers that have been designated as global catalog serversand is distributed through
multimaster replication.