1. [单选题]On a half-duplex Ethernet LAN, two hosts attempt to send data simultaneously, resulting in a collision. Following this collision, what will the hosts do? (Select all valid answers)
A. The destination host sends a request to the source for retransmission.
B. The jam signal indicates that the collision has been cleared.
C. The hosts will attempt to resume transmission after a time delay has expired.
D. An electrical pulse indicates that the collision has cleared.
E. The router on the segment will signal that the collision has cleared.
F. F. The hosts will do nothing, as the higher layers are responsible for data error correction and re-transmission.
2. [单选题]两台路由器直连到一起，应该使用的线缆为（）
A. 交叉线缆
B. 直通线缆
C. 反转线缆
D. 任意线缆
3. [单选题]路由器上的命令“show version”的功能是（）
A. 显示版本信息
B. 显示端口配置信息
C. 显示路由表
D. 显示路由协议信息
