You have an Exchange Server 2010 organization.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？（）
- AActive Directory Users and Computers
- BExchange Control Panel （ECP）
- CExchange Management Console （EMC）
- DMicrosoft Office Outlook