单项选择题
A.VLAN instance mapping and revision number
B.VLAN instance mapping and member list
C.VLAN instance mapping， revision number， and member list
D.VLAN instance mapping， revision number， member list， and timers
单项选择题 Refer to the exhibit. Switch 15 is configured as the root switch for VLAN 10 but not for VLAN 20. If the STP configuration is correct， what will be true about Switch 15？（）
多项选择题 WhichtwostatementsaretrueaboutBPDUport-guardandBPDUfiltering？（）
单项选择题 Refer to the exhibit and the partial configuration of switch SW_A and SW_B. STP is configured on all switches in the network. SW_B receives this error message on the console port： 00：06：34： %CDP-4-DUPLEX_MISMATCH： duplex mismatch discovered on FastEthernet0/5 （not half duplex）， with SW_A FastEthernet0/4 （half duplex） ， with TBA05071417（Cat6K-B） 0/4 （half duplex）. What would be the possible outcome of the problem？（）