You have an Exchange that contains the exchange servers shown in the following table： You plan to move all mailboxes from server2 and server3 to server4.  You need to ensure that all users can send and receive e-mail messages after their mailboxes are moved to server4.What should you do？（）

• A、Create an SMTP Site Link.
• B、Create a Routing Group and a Routing Group Connector.
• C、Install the Exchange Server 2010 Hub Transport Server Role on Server4.
• D、Install the Exchange Server 2010 Edge Transport server role on a new server.