A customer wants to provide remote disaster recovery (DR) for several critical mailbox servers in their Microsoft Exchange Server 2007 environment. Local recoverability is provided by creating…

A customer wants to provide remote disaster recovery (DR) for several critical mailbox servers in their Microsoft Exchange Server 2007 environment. Local recoverability is provided by creating replicas of their critical databases. The customer's DR site is located 20 km away. They have already provisioned the necessary failover host on the DR site, as well as the required Active Directory infrastructure needed to support a failover. However, they want to minimize the total number of database copies required to provide basic failover capabilities for the Exchange server. Which solution would you recommend to provide remote point-of-failure recovery with the fewest local and remote database copies?