Your network contains a single Active Directory forest. The forest contains two domain trees named
contoso.com and fabrikam.com. You have an Exchange Server 2010 organization. The e-mail
addresses for the organization are configured as shown in the following table. You need to ensure
that all outbound e-mail messages from fabrikam.com appear to originate from contoso.com. Users
in contoso.com must be able to send e-mail messages to users in fabrikam.com by using the address
format alias@fabrikam.com. What should you do first?

A.
Deploy an Edge Transport server.

B.
Deploy a Microsoft Internet Security and Acceleration (ISA) server.

C.
Modify the accepted domain entry for contoso.com.

D.
Modify the accepted domain entry for fabrikam.com.

Explanation:
A is the correct answer as you will need to do an address rewrite to make email appear that it has
originated from contoso.com. This can only be done with the Edge Transport Server