Thedefaultbehaviorofswitchingtotheshortestpathtreeassoonasanewsourceisdetectedonthesharedtreecanbedisabledbysettingthevalueintheippimspt－thresholdcommandto'zero.'（）

A.loopguard
B.stormcontrol
C.stormsuppression
D.broadcastsuppression
E.BPDUguard

【参考答案】

B, D