Your network contains an internal network and a perimeter network. The internal network contains a single Active Directory site.  The perimeter network contains two Exchange Server 2010 Edge Transport servers. You plan to deploy an Exchange Server 2010 organization on the internal network.  You need to plan the deployment of Hub Transport server roles to meet the following requirements：.If a single Hub Transport server fails， e-mail messages from the Internet must be delivered to the Mailboxservers. .If a single Hub Transport server fails， users must be able to send e-mail messages to other users thathave mailboxes on the same Mailbox server.  What should you include in the plan？（）

• A、Deploy one Edge Transport server on the internal network， and then configure EdgeSync  synchronization.
• B、Deploy one Hub Transport server on the internal network， and then configure EdgeSync  synchronization.
• C、Deploy one Hub Transport server on the internal network and one Hub Transport server on the   perimeter network.
• D、Deploy two Hub Transport servers on the internal network.