多项选择题 Refer to the exhibit. A junior network administrator was given the task of configuring port security on SwitchA to allow only PC_A to access the switched network through port fa0/1. If any other device is detected, the port is to drop frames from this device. The administrator configured the interface and tested it with successful pings from PC_A to RouterA, and then observes the output from these two show commands.Which two of these changes are necessary for SwitchA to meet the requirements? （）

多项选择题 Which two of these statements are true of IPv6 address representation? （）

单项选择题 Refer to the exhibit. When running OSPF, What would cause router A not to form an adjacency with router B?（）