You have a hosted Exchange organization. All servers in the organization have Exchange
Server 2010 Service Pack 1 (SP1) installed.
You have a user named User1 and a user named User2.
You need to ensure that User1 can add User2 to the From field when he sends e-mail
messages. Messages that have User2 in the From field must display only User2 as the
message sender to recipients who receive the messages.
What should you use?

A.
Exchange Management Console (EMC)

B.
Microsoft Outlook

C.
Exchange Control Panel (ECP)

D.
Active Directory Users and Computers

Explanation:
http://technet.microsoft.com/en-us/library/bb676368.aspx
EMC is used to manage the permissions.