The correct answer is C. response time.
Response time is the time it takes for a system to react to an input. In the context of a keyboard, response time is the time it takes for the computer to display the character that was typed on the keyboard.
Key is the physical object that is pressed to input a character. System review is the process of checking the system for errors. Batch processing is a type of processing in which a group of tasks are executed together.
None of the above is not a correct answer.