单项选择题
A. UDLD （UniDirectional Link Detection）
B. spanning-tree loopguard
C. VTP mode transparent
D. switchport mode desirable
单项选择题 WhichIGMPv2messagecontainsanon-zero"MaxResponseTime"？（）
单项选择题 Apartfrominterdomainmulticastrouting，whatelseisMSDPusedfor？（）
单项选择题 Refer to the exhibit. Look at the command output. Assume that there is no other path， and the configuration is correct. What would be the consequences of this situation？（）
