Your network consists of a single Active Directory domain named contoso.local. You deploy Exchange Server 2003 on the network.
You need to ensure that all mailbox-enabled users are assigned a SMTP e-mail address that uses the firstName.lastName@contoso.com format.
What should you do?

A.
Add a UPN suffix.

B.
Create a new address list.

C.
Modify the default recipient policy.

D.
Create a new mailbox store system policy.