单项选择题
A. Because the configuration revision of the new switches is lower than the rest of the network，it can change the VLAN database of the other switches.
B. As a VTP server， the new switch deleted all VLANs of the network.
C. Erasing VLANs increases the VTP configuration revision.
D. Since the configuration revision of the network is higher than the new switch，the VLAN database was automatically synchronized.
多项选择题 Refer to the exhibit. Users from the Engineering VLAN complain that every time Business VLAN users have a network connectivity issue， the Engineering VLAN users usually have problems experiencing slow response or network connectivity problems. After troubleshooting， an unauthorized switch 2 was found. This unauthorized switch has been a regular problem， assuming the root bridge function under the spanning-tree domain and causing the Engineering VLAN to be unstable. Which three of these actions could be suggested to fix the problem？（）
单项选择题 WhatistrueaboutIPSourceGuardwithportsecurity？（）
单项选择题 Refer to exhibits 1 and 2. In exhibit 1， all users on the LAN segment use router A as the active HSRP router. Router B is the standby router for the HSRP. In exhibit 2， the network management team reported that there is no utilization on the WAN link B. To solve this problem， you decide to change the logical topology of your LAN， but you are not sure about what changes must be made. You must manage HSRP or change it to another protocol in order to provide the most scalable design， automatic redundancy， and load balancing. Which one of these actions would be the best choice？ （）