Your company has a single Active Directory domainnamed intranet.contoso.com.
All domain controllersrun Windows Server 2008 R2.
The domain functional levelis Windows 2000 nativeand the forest functional levelis Windows 2000.
You need to ensure the UPN suffix for contoso.com is available for user accounts.
What should you do first?

A.
Raise the intranet.contoso.com forest functional level to Windows Server 2003 or higher.

B.
Raise the intranet.contoso.com domain functional level to Windows Server 2003 or higher.

C.
Add the new UPN suffix to the forest.

D.
Change the Primary DNS Suffix option in the Default Domain Controllers Group Policy Object (GPO) to
contoso.com.

Explanation:
http://support.microsoft.com/kb/243629
HOW TO: Add UPN Suffixes to a Forest
Adding a UPN Suffix to a Forest
Open Active Directory Domains and Trusts.
Right-click Active Directory Domains and Trustsin the Tree window pane, and then click Properties.
On the UPN Suffixes tab, type the new UPN suffix that you would like to add to the forrest.
Click Add, and then click OK.
Now when you add users to the forest, you can select the new UPN suffix to complete the user’s logon name.
APPLIES TO
Microsoft Windows 2000 Server
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Datacenter Server