Your company has two main offices named Main1 and Main2.An Active Directory site exists for each office. Users connect locally to servers in both offices. 
The offices connect to each other by using a high-speed WAN link. You plan to deploy Exchange Server 2010. 
You need to plan the deployment of Mailbox servers to meet the following requirements：
.Ensure that users can access their mailbox from a server in their site， if a single Mailbox server fails 
.Ensure that users can access their mailboxes remotely if a site fails 
.Minimize the number of servers
How many Mailbox servers should you include in the plan？（）

Your network contains two data centers named Datacenter1 and Datacenter2. An Active Directory site exists for each data center. 
The data centers connect to the Internet by using a direct link. 
The data centers connect to each other by using a high-speed WAN link. 
You plan to deploy Exchange Server 2010 Mailbox servers in both data centers. You need to plan message routing to meet the following requirements：.Ensure outbound delivery of e-mail messages if a single server fails .Automatically load balance the Hub Transport server in each site .Deploy the minimum number of servers
What should you include in the plan？（）