Which one of the following groups have only input devices?Select the correct answer from the code given below:

1. A

   Mouse, Keyboard, Printer

   Option (a) claims that Mouse, Keyboard, and Printer are all input devices. However, a printer is an output device used to produce hard copies of documents, making this group incorrect.

2. B

   Mouse, Keyboard, Projector

   Option (b) lists Mouse, Keyboard, and Projector as input devices. A projector is an output device used to display computer output on a larger screen, which invalidates this option.

3. C

   Mouse, Keyboard, Monitor

   Option (c) includes Mouse, Keyboard, and Monitor as input devices. Since a monitor acts as a primary output device to display visual information, this group is also wrong.

4. D

   Mouse, Keyboard, Scanner

   Option (d) correctly states that Mouse, Keyboard, and Scanner are all input devices used to feed data and instructions into a computer system. The mouse and keyboard allow user interaction, while the scanner converts physical documents into digital formats, fulfilling all criteria for input hardware and thus making this the official key.

Summary. Official key is (d) Mouse, Keyboard, Scanner. This question tests the fundamental distinction between computer input and output devices. While options (a), (b), and (c) all contain at least one output device such as a printer, projector, or monitor, option (d) exclusively lists hardware designed to input data. Aspirants must carefully differentiate peripheral types to avoid common confusion in basic computer awareness questions.