A corporate network contains a Windows Server 2008 R2 Active Directory forest.
You need to add a User Principle Name (UPN) suffix to the forest.
What tool should you use?

A.
Dsmgmt.

B.
Active Directory Domains and Trusts console.

C.
Active Directory Users and Computers console.

D.
Active Directory Sites and Services console.

Explanation:
http://www.kassapoglou.com/windows-server-2008-lesson-23-video-creating-a-user/
Demonstration adding a UPN Suffix
To add or modify a UPN suffix for your forest, open Active Directory Domains and Trusts
from the start menu.
Right click Active Directory Domains and Trusts at the top and open the properties. From
here you can add and remove additional domain UPN suffixes for the forest.