You work as the enterprise exchange administrator at Xxx .The Xxx network consists of a domain named xxx .The Xxx network has three mail servers named XXX-SR11， XXX-SR12 and XXXSR13 that has the following implementation：  （1）2003 SP2.  （2）2003 SP2.  （3）running Exchange Server 2010.  How can you perform the migration of the mailboxes from XXX-SR12 to XXX-SR13 and to assure the availability of the mailboxes？（）

• A、You should implement recipient filtering.
• B、You should configure EdgeSync synchronization.
• C、You should implement Transport Protection Rules.
• D、You should deploy the Exchange Server 2010 Hub Transport server role.