Answer : 4. "Monitor and Printer"
Explanation :

An output device is a computer hardware device that displays or reproduces information processed by a computer in human-readable form. Output devices usually receive information from the computer through an input device, such as a mouse or keyboard.

Some examples of output devices include-

1. Monitor: A monitor is a visual output device that displays images generated by a computer.

2. Printer: A printer is a physical output device that prints computer-generated documents on paper.

3. Speaker: A speaker is an audio output device that reproduces the sound produced by the computer.

4. Headphone: A headphone is a personal audio output device that reproduces the sound generated by a computer solely for the user to hear.

5. Projector: A projector is similar to a monitor, but it projects images onto a larger screen.

6. GPS Device: A GPS device is an output device that displays its current location to the user on a map or other view.

7. Braille Reader: A Braille reader is an output device that displays computer-generated information in Braille for visually impaired people.