You are a messaging professional. Your company deploys both Microsoft Exchange Server 2003 and Microsoft Exchange Server 2007 computers.

Client Access Servers are deployed on the company network. Only the Client Access Servers are accessible on the Internet.

Users access their Exchange mailboxes on the Internet by using Microsoft Office Outlook Express. All mailboxes for POP3 clients and IMAP4 clients are located on the Exchange Server 2003 back-end servers.

You need to ensure that all POP3 and IMAP4 client connections are authenticated and encrypted.

What should you do to ensure that all POP3 and IMAP4 client connections are authenticated and encrypted?

A.
Deploy X.509 certificates for the POP3 clients and the IMAP4 clients on the Exchange Server 2003
back-end server.

B.
Deploy X.509 certificates for the POP3 clients and the IMAP4 clients on the Exchange Server 2007 Client
Access Servers.

C.
Deploy IPSec encryption between the Exchange Server 2007 Client Access Servers and the Exchange
Server 2003 back-end servers.

D.
Configure secure authentication for the POP3 clients and the IMAP4 clients on the Exchange Server 2007
Client Access Servers.