Answer:

To determine which group consists of only input devices, we need to understand what input devices are and identify them among the given options.

Input devices:
Input devices are hardware devices that allow users to input data, commands, and instructions into a computer or other digital device. These devices enable communication between the user and the computer, allowing the user to interact with and control the system. Common examples of input devices include a mouse, keyboard, scanner, and more.

Given options:
a) Mouse, Keyboard, Scanner
b) Mouse, Keyboard, Plotter
c) Mouse, Keyboard, Printer
d) Mouse, Keyboard, Monitor

Analysis:
To determine which group consists of only input devices, we need to identify the devices in each option that are considered input devices.

a) Mouse, Keyboard, Scanner:
- The mouse and keyboard are both input devices as they allow the user to input commands and data into the computer.
- The scanner, on the other hand, is an output device as it takes physical documents and converts them into digital form, which is an output from the scanner.

b) Mouse, Keyboard, Plotter:
- The mouse and keyboard are input devices.
- A plotter, however, is an output device that is used to produce physical copies of digital designs or drawings. It takes digital data from the computer and outputs it onto paper or other materials.

c) Mouse, Keyboard, Printer:
- The mouse and keyboard are input devices.
- A printer, like a plotter, is an output device as it takes digital data from the computer and produces physical copies on paper or other materials.

d) Mouse, Keyboard, Monitor:
- The mouse and keyboard are input devices.
- A monitor is an output device that displays the visual output of the computer system.

Conclusion:
After analyzing the given options, we can conclude that group a) consisting of the mouse, keyboard, and scanner consists of only input devices. The mouse and keyboard allow the user to input commands and data, while the scanner was incorrectly listed as an input device.