Question

a set of keys used to type letters and numbers into the computer. microphone motherboard graphics card keyboard

Explanation:

A keyboard is a set of keys used to input letters and numbers into a computer. The other options (microphone, motherboard, graphics - card) have different functions. A microphone is for audio input, a motherboard is the main circuit board of a computer, and a graphics card is for handling visual output.

Answer:

Keyboard