Your network contains two Active Directory sites. The sites connect to each other by using a WAN link. You plan to deploy two Exchange Server 2010 Mailbox servers and two Client Access servers in eachsite. Each site will contain a Client Access array. You need to recommend a solution to deploy Hub Transport servers. The solution must meet the following requirements：.Continue to deliver e-mail messages to users in other sites if a single Hub Transport server fails .Support the planned Client Access array deployment.Minimize the number of Exchange servers What are two possible ways to achieve this goal？（）

Add the Hub Transport server role to each Mailbox server.
B. Add the Hub Transport server role to each Client Access server.
C. Deploy two Hub Transport servers on two new servers in each site.
Deploy one Hub Transport server on a new server， and then install the SMTP service on each Client Access server.