Someusersreporttheycannotreceivemessagesfromsomeexternalsenders.Yoususpectthatthereissomeanti-spamactivityblockingthosemessages.Youneedtoidentifywhatisblockingthemessages.Youwillactivateandreviewthelogsofoneofthefollowing（）
A.Protocollogging
B.Connectivitylogs
C.Messagetracking
D.Pipelinetracing
参考答案：C
