Your organization has one Exchange Server 2003 server named Server1.
You deploy a custom application on Server1. The application is configured to send e-mail messages to a mailbox named App1.
The return address on messages sent by the application is Server1@contoso.com.
You need to ensure that the App1 mailbox only receives messages sent from Server1@contoso.com.
What should you do?

A.
Configure the SMTP virtual server on Server1 to relay e-mail for messages sent from the server’s local IP address.

B.
Configure the application to use authentication when sending e-mail. Configure The App1 mailbox to accept messages only from authenticated users.

C.
Create a mail-enabled contact named Server1 that has a Server1@contoso.com e-mail address. Configure the App1 mailbox to only accept messages from the Server1 contact.

D.
Create a mailbox-enabled user named Server1 that has a Server1@contoso.com e-mail address. Assign Receive As permissions for the App1 mailbox to the Server1 user account.