单项选择题
Refer to the exhibit. Which switching feature is being tested？（）
A. loop guard B. PortFast C. root guard D. BDPU guard
多项选择题 WhichtwooptionsdoesCiscoPfRusetocontroltheentrancelinkselectionwithinboundoptimization？（）
多项选择题 WhichthreecombinationsarevalidLACPconfigurationsthatwillsetupachannel？（）
单项选择题 In802.1s，howistheVLANtoinstancemappingrepresentedintheBPDU？（）
