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？（）

• A、Windows Server Backup
• B、Network Attached Storage （NAS） snapshots
• C、Microsoft System Center Configuration Manager
• D、Microsoft System Center Data Protection Manager