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 fromcontoso.com.  Users in contoso.com must be able to send e-mail messages to users in fabrikam.com by using theaddress 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.