指定同/异步串口1和2的备份优先级分别为10和20的配置为()
A、backup interface 1 10; backup interface 2 20
B、backup interface serial 1 10; backup interface serial 2 20
C、backup interface 1 priority 10; backup interface 2 priority 20
D、backup interface serial 1 priority 10; backup interface serial 2 priority 20