should be C router
explanation: router is a layer 3 device based on logical address ip address to realize the forwarding campus is a big network telecom isp assigns an ip under the several subnets metropolitan area network is also the same link between the two different segments of the network with a router
switch is used to separate the conflicting domains to realize the forwarding function generally used for local area network. Separation of conflicting domains, forwarding, generally used in LANs
Excuse me if I'm not very good at expressing myself
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