What is the Internet?

A. A way of sending messages electronically
B. A collection of linked documents called Web pages
C. A collection of computers that are linked together
D. Related Web pages that are grouped together

"A collection of computers that are linked together" is the Internet.

Option C

Explanation:

To connect to the Internet and other computer systems on the networks, a network interface cards (NIC) must be installed on the computer. A network cable connected to one end of the NIC and connected to a cable modem, DSL modems, switch or router can allow your computer to connect to the Internet and connect to other computers.

In the rest of all other networks, computers with Windows or Mac have easy access to an internet connectivity. You can even turn your computer into a wireless access points so you don't need a router to pair wireless devices.