单项选择题

路由器查看端口状态,下面()表示端口处于关闭状态(以S0/3/0口为例)。

A.S0/3/0 is down,line protocol is down
B.S0/3/0 is up,line protocol is down
C.S0/3/0 is up,line protocol is up
D.S0/3/0 is administratively down,line protocol is down