5864当学生A用两台Star-R2624路由器在做路由器广域网口连通实验时误将本端路由器V.35线缆的插头插倒6880

当学生A用两台Star-R2624路由器在做路由器广域网口连通实验时误将本端路由器V.35线缆的插头插倒了。结果发现ping直连的路由器不通，请问此时查看本端路由器的状态应该是：() A.Serial 0 is up, line protocol is up B.Serial 0 is up, line protocol is down C.Serial 0 is down, line protocol is down D.Serial 0 is down, line protocol is up E.Serial 0 is administratively down, line protocol is down F.Serial 0 is administratively down, line protocol is up 请帮忙给出正确答案和分析，谢谢！