What signal does a computer interpret when a user presses a key on the keyboard?

The correct answer is ASCII value. When a user presses a key on the keyboard, the computer translates that physical action into a specific code that it can understand, and one of the primary encoding schemes used for this purpose is ASCII (American Standard Code for Information Interchange).

ASCII represents characters as numerical values. For example, when the 'A' key is pressed, the computer generates a binary signal that corresponds to the ASCII value of 'A', which is 65 in decimal or 01000001 in binary. This allows the computer to recognize which key was pressed and process that input accordingly.

While other forms of encoding and signals exist (such as binary signals and character codes), the ASCII value is specific to how text characters are represented in a standard format, making it the most accurate choice in the context of keyboard inputs.