Which of the following answers are true about routers, switches, and gateways?

a$.$

Router is a networking device which can select an appropriate path for transferring data packages between different networks. Routers are connected at the network layer. Using headers and routing tables, routers determine the best path for forwarding the packets using routing algorithm.

b$.$

Switch is used to set up direct connection for exchanging between two or more computers. In the OSI communications model, a switch performs the layer $2$ function.

c$.$

Gateway is a point of entry or exit in a network, enabling connection to other networks. To access a network, we need to know its gateway. All data going out passes through the gateway.

d$.$

All of the above.

e$.$

None of the above.