单项选择题
A.They have been configured with the spanning-tree bpdufilter disable command.
B.They have been configured with the spanning-tree bpdufilter enable command.
C.They have been configured with the spanning-tree bpduguard disable command.
D.They have been configured with the spanning-tree bpduguard enable command.
E.They have been configured with the spanning-tree guard loop command.
F.They have been configured with the spanning-tree guard root command.
单项选择题 Refer to the exhibit. STP has been implemented in the network. Switch SW_A is the root switch for the default VLAN. To reduce the broadcast domain， the network administrator decides to split users on the network into VLAN 2 and VLAN 10. The administrator issues the command spanning-tree vlan 2 root primary on switch SW_A. What will happen as a result of this change？（）
单项选择题 Refer to the exhibit. The command switchport mode access is issued on interface FastEthernet0/13 on switch CAT1. What will be the result？（）
单项选择题 Refer to the exhibit. What will happen when one more user is connected to interface FastEthernet 5/1？ （）
