单项选择题
A. Router A is the master virtual router， and Router B is the backup virtual router. When Router A fails， Router B will become the master virtual router. When Router A recovers， Router B will maintain the role of master virtual router.
B. Router B is the master virtual router， and Router A is the backup virtual router. When Router B fails， Router A will become the master virtual router. When Router B recovers， it will regain the master virtual router role.
C. Router A is the master virtual router， and Router B is the backup virtual router. When Router A fails， Router B will become the master virtual router. When Router A recovers， it will regain the master virtual router role.
D. Router B is the master virtual router， and Router A is the backup virtual router. When Router B fails， Router A will become the master virtual router. When Router B recovers， Router A will maintain the role of master virtual router.
单项选择题 Exhibit： Exhibit： You work as a network engineer at Company. You study the exhibit carefully. Which GLBP device hosts receive the MAC address assignment？（）
多项选择题 On a 3550 EMI switch， which three types of interfaces can be used to configure HSRP？ （）
单项选择题 Which command will need to be added to External_A to ensure that it will take over if serial 0/0 on External_B fails？ （）
