Which of the following is NOT an input device?

The printer is the correct answer as it is not an input device; rather, it functions as an output device. Input devices are tools that allow users to enter data or commands into a computer system. For example, a microphone captures audio input, a webcam captures video input, and a keyboard allows users to input text and commands. In contrast, a printer takes information from a computer and produces a physical copy, therefore serving the purpose of output, not input. This distinction is essential for understanding how different devices interact with a computer and the roles they play in data processing.