You have an Exchange organization.All servers in the organization have Exchange Server 2010 Service Pack l （SP1） installed.An external user reports that when he sends e-mail messages to the organization， they are not received.You suspect that the e-mail messages he sends are incorrectly identified as spam.You need to identify which anti-spam filter is blocking the e-mail messages. What should you do？（）

• A、Modify the protocol logging level， and then review the protocol logs.
• B、Modify the connectivity log settings， and then review the connectivity logs.
• C、Modify the message tracking settings， and then review the message tracking logs.
• D、Enable pipeline tracing， and then review the trace.