The correct answer is: C. Acoustic coupler.
An acoustic coupler is a device that allows a computer to communicate with a telephone line using a standard telephone handset. It consists of two cups that fit over the mouthpiece and earpiece of the telephone, and a microphone and speaker that connect to the computer. When the computer is in use, the acoustic coupler converts the digital signals from the computer into audio signals that are transmitted over the telephone line. The telephone handset converts the audio signals back into digital signals that are received by the computer.
Acoustic couplers were once a common way to connect computers to the internet, but they have been largely replaced by modems and other technologies. However, they are still used in some cases, such as when a computer does not have a built-in modem or when a user needs to connect to a dial-up internet service.
Light pen is a pointing device that uses a light beam to detect the position of a cursor on a computer screen. It was invented in 1952 by Ben Laposky and was first used in the 1960s on the TX-0 computer at MIT. Light pens are no longer commonly used, but they were once a popular way to interact with computers.
Mouse is a pointing device that is used to control the cursor on a computer screen. It was invented in 1964 by Douglas Engelbart and was first used on the Xerox Alto computer in 1973. Mice are now the most common pointing device used with computers.
Touch panel is a type of input device that allows users to interact with a computer by touching the screen. Touch panels are used on many different types of devices, including smartphones, tablets, and laptops.
None of the above is not the correct answer.