单项选择题
WhatwilloccurwhenanonedgeswitchportthatisconfiguredforRapidSpanningTreedoesnotreceiveaBPDUfromitsneighborforthreeconsecutivehellotimeintervals?()
A.RSTPinformationisautomaticallyagedout.
B.TheportsendsaTCNtotherootbridge.
C.Theportmovestolisteningstate.
D.Theportbecomesanormalspanningtreeport.