单项选择题

用户的路由器使用FrameRelay联网,误码测试正常,但是帧中继测试不正常,用户电路不能使用,则用show interface s0命令查看的结果应该为()

A.interface s0 is up ,protocaol is up
B.interface s0 is up ,protocaol is down
C.interface s0 is down ,protocaol is up
D.interface s0 is down ,protocaol is down