You have an Exchange Server 2010 organization that contains an accepted domain named
contoso.com.
The Exchange organization contains a DAG named DAG1. The organization also contains
one public folder database called PF1.
You need to configure public folder replication to the other servers in the DAG.
What should you do first?

A.
Use the Set-DatabaseAvailabilityGroup cmdlet.

B.
Use the New-PublicFolderDatabase cmdlet.

C.
Use the Set-PublicFolderDatabase cmdlet.

D.
Use the Exchange Management Console (EMC) to modify the properties of PF1.

Explanation:
A new public folder database is required on all members of the DAG, if you wish to replicate
the public folder across to them:
A public folder database can be hosted on a Mailbox server in a database availability group
(DAG), but you must use multiple public folder databases and public folder replication for
data redundancy. When you modify a public folder or its contents, the public folder database
that contains the replica of the public folder that was changed sends a descriptive email
message to the other public folder databases that host a replica of the public folder.

http://technet.microsoft.com/en-us/library/bb629523.aspx