Which of the following devices is considered an input device?

The keyboard is classified as an input device because it allows users to enter data and commands into a computer or other digital systems. Input devices are specifically designed to capture user actions or input, facilitating interaction with the computer. A keyboard consists of keys for different characters, symbols, and functions, enabling users to input text, numbers, and commands efficiently.

In contrast, monitors, printers, and speakers are output devices. Monitors display visual output from the computer, printers produce physical copies of documents and images, and speakers generate audio output. Thus, while all these devices play vital roles in a computing environment, only the keyboard fits the definition of an input device.