You need to identify why a remote SMTP server rejects email sent from the organization.

You have an Exchange organization. All servers in the organization have Exchange Server 2010 SP1 installed.

You need to identify why a remote SMTP server rejects email sent from the organization.

What should you do?

A.
Modify the diagnostic logging level on the MSEchangeTransportService object, and then review the Application event log.

B.
Modify the connectivity log settings on the Transport server, and then review the connectivity logs.

C.
Modify the message tracking settings on the Transport server, and then review the message tracking logs.

D.
Modify the protocol logging level on the Send connectors, and then review the protocol logs.

Explanation:
Protocol logging records the SMTP conversations that occur between email servers as part of message delivery. These SMTP conversations occur on Send connectors and Receive connectors configured on servers running Microsoft Exchange Server 2010 that have the Hub Transport server role or the Edge Transport server role installed. You can use protocol logging to diagnose mail flow problems.

Reference:

http://technet.microsoft.com/en-us/library/bb124531.aspx