Which of the following uses TCP?（）

A.Transport
B.Presentation
C.Session
D.Application

A. Performs switching and routing duties
B. A router that directly connects to a switch
C. A multi-purpose switch fabric used in full mesh environments
D. A switch that directly connects to a router

A. the cause of routing errors.
B. the number of switches on the network.
C. the number of users on the network.
D. where network latency will occur.