An internet is a combination of networks c
题型：单项选择题
问题：
An internet is a combination of networks connected by (1).When a datagram goes from a source to a(2)，it will probably pass many (3)until it reaches the router attached to the destination network. A router receives a (4)from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5)is the optimum pathway?
空白（1）处应选择（）
A.modems
B.routers
C.switches
D.computers
