Asystemadministratorreceivedthefollowingmessagewhiletryingtosshtoaserverconnectiontimedout.Theadministratorpingedtheserverandhadnoresponse.Theadministratorthenpingedthegateway，andwassuccessful.Whichtoolcouldtheadministratorusenexttoisolatetheproblem？（）
A.route
B.traceroute
C.netstat-nr
D.broadcastping
参考答案：B
