Communication channel:It Is used to convey information between two entities.Channel has certain capacity for transmitting information is measured by its bandwidth in hertz.Some medium through which we can transmit the information Cable Wire etc.Network:It is a collection of computers, servers, network devices or other devices connected to one another to allow the sharing of data.Example of Network: Internet (Which connects billions of people all over the world)Modem:Receives information from your ISP through any medium (optical fibre or phone lines etc) in your home and converts it into a digital signal.Works likes translation between ISP and Router.Bus: It is used to connect computer components and transfer data between them.Example: An internal bus connects computer internals to motherboardHence option 2 is the correct answer.