You have an Exchange Server 2010 organization. 
The network contains two Mailbox servers that are configured in a database availability group （DAG）. You plan to implement a disaster recovery solution. 
You need to recommend a solution that ensures that the active mailbox database copy is unaffected bythe backup process. 
You want to achieve this goal while minimizing costs. 
What should you recommend？（）

Your company has a main office and 10 branch offices. Each office connects to the Internet by using a direct link. 
The main office connects to the branch offices by using a WAN link. You plan to deploy Exchange Server 2010 servers in each office. 
You need to design Active Directory to meet the following Exchange Server 2010 requirements：.Users must be able to access their mailboxes if a single domain controller fails .Users must be able to send e-mail messages to the Internet if a WAN link fails 
What should you include in the design？（）