Your network contain an Active Directory forest. The forest contains a single domain named
contoso.com. The network contains a legacy mail system that uses a SMTP namespace of
contoso.com.
You plan to deploy Exchange Server 2013.
There will be a period of interoperability while the email is migrated from the legacy system to
Exchange Server 2013.
During the period of interoperability, you need to ensure that all incoming email is received by an
Exchange Server 2013 server, and then routed to the legacy mail system if an Exchange Server email
recipient cannot be found.
You configure the firewall in the perimeter network to route SMTP traffic to the Exchange Server
2013 organization.
What should you do next?

A.
Modify the existing accepted domain for contoso.com and create a new Send connector.

B.
Add a new external relay accepted domain for contoso.com and create a new Send connector.

C.
Add a new authoritative domain for contoso.com and create a new email address policy.

D.
Add a new internal relay accepted domain for contoso.com and create a new email address
policy.