单项选择题
Thefollowingwasconfiguredonaswitch：Switch（config）spanning－treeportfastbpdufilterdefaultWhatistheeffectofthisconfigurationcommand？（）
A.IfBPDUsarereceivedbyaportconfiguredforPortFast，theyareignoredandnonearesent.
B.ThecommandwillenableBPDUfilteringonallportsregardlessofwhethertheyareconfiguredforBPDUfilteringattheinterfacelevel.
C.IfBPDUsarereceivedbyaportconfiguredforPortfast，theportwilltransitiontoforwardingstate.
D.IfBPDUsarereceivedbyaportconfiguredforPortFast，thenPortFastisdisabledandtheBPDUsareprocessednormally.
E.Noneoftheotheralternativesapply.