You have an Exchange 2010 that contain DAG named DAG1.DAG1 contains two Mailbox Servers named Server1 and Server2.5 Mailbox Database are replicated in DAG1.You need to install Exchange Rollup update on Server1.The solution must not prevent user from accessing their Mailboxes. What should you do first？（）

• A、Run the Set-MailboxDatabase cmdlet， and then configure all mailbox Database copies as lagged copies
• B、Run the Suspend- MailboxDatabasecopy cmdlet， and then switch over all mailbox database to Server2
• C、Run the Update- MailboxDatabasecopy cmdlet， and then modify the mailbox database Activation preference
• D、Run the Set-DatabaseAvailabilityGroup cmdlet， and then enable Datacenter Activation Coordination