单项选择题 The network administrator has discovered that the power supply has failed on a switch in the company LAN and that the switch has stopped functioning. It has been replaced with a Cisco Catalyst 2950 series switch. What must be done to ensure that this new switch becomes the root bridge on the network?（）

单项选择题 Which command shows if an access list is assigned to an interface?（）

单项选择题 A wireless client cannot connect to an 802.11b/g BSS with a b/g wireless card. The client section of the access point does not list any active WLAN clients. What is a possible reason for this?（）