Refer to the exhibit． A technician is troubleshooting a host connectivity problem． The host is unable to ping a server connected to Switch_A． Based on the results of the testing, what could be the problem?

A、 A remote physical layer problem exists．
B、 The host NIC is not functioning．
C、 TCP/IP has not been correctly installed on the host．
D、 A local physical layer problem exists．

【正确答案】 D

【答案解析】主机ping 自己能够ping通自己，但是包无法发送出去，表明自己的物理层有问题存在。而因为能够ping通自己，表明TCP/IP的协议栈运行是良好的。