You have an Exchange Server 2010 server named Server1. Server1 hosts a mailbox
database named DB1 that contains 25 user mailboxes.
You create a new public folder database named PUB2.
You need to configure PUB2 as the default public folder database for each mailbox on DB1.
Which properties should you modify?

A.
Modify the properties of each mailbox.

B.
Modify the properties of DB1.

C.
Modify the properties of Server1.

D.
Modify the properties of PUB2.

Explanation:

http://technet.microsoft.com/en-us/library/bb629522.aspx