Why would a switch be used in networks in preference to a hub?
(A) To reduce the network traffic
(B) To prevent the spread of all viruses
(C) to connect a computer directly to the internet
(D) to manage password security at the workstation.

Hint Switches are smarter than hubs in a network system. Hubs sends all information passing through it to all computers connected to it. This may cause a lot of network traffic.

Complete step by step answer
A computer network in general is simply a situation or configuration in which two or more computers are connected together for the purpose of data transfer between them. The connections can either be made through wires such as Universal Serial Bus (USB), LAN cables, or connected wirelessly directly or indirectly through devices like routers. There are, of course different types of network configuration, called network topology each with its own advantages and disadvantages.
A hub, in simple terms is a networking device which allows multiple computers to be connected together as a single network. When hubs are used to connect computers together, the devices cannot communicate directly but through the hub as an intermediate device. This allows all information to go through it which may generate data traffic. The post notable and distinct characteristics of hub is that it sends data received by it from one computer to every computer connected to it irrespective of intended target.
Switch, on the other hand, is a network device which acts similarly to a hub but intelligent such that it transfers information only to intended targets. Hence, this reduces the data network traffic.
Hence, the correct option is A.

Note
To avoid confusions, the switch being mentioned here is a networking device thus, an electronic device, and has both software and hardware components. It is not the electrical device used in opening and closing a circuit.