1. [单选题]Which one of the following characteristics is true regarding the use of hubs and switches?
A. Hubs can have their ports be configured with VLANs
B. Using hubs is costly with regard to bandwidth availability.
C. Switches can not forward broadcasts.
D. Switches are more efficient than hubs in processing frames.
E. Switches increase the number of collision domains in the network.
2. [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
