Final answer:
Input devices are used for entering data into a computer system, whereas output devices are used for displaying data from the computer to the user.
Step-by-step explanation:
The function of an input device is to allow users to enter data into a computer. Common examples of input devices include keyboards, mice, and scanners. On the other hand, the function of an output device is to present data from the computer to the user in a readable or usable form. Output devices include monitors, printers, and speakers.
Answering the student's question, the correct option is: a) Input device: Entering data; Output device: Displaying results. This means that input devices are used for data entry such as typing text or capturing images, while output devices are used to display or output the processed data, such as showing text on a screen or printing a document.