Final answer:
A keylogger is a device or a piece of software used to record keystrokes. It is designed to monitor and capture every key pressed on a keyboard. The correct answer to the question is d) keylogger.
Step-by-step explanation:
The device used to capture keystrokes is known as a keylogger. A keylogger can be either a physical device that plugs into a computer or it can be a piece of software that records the keys struck on a keyboard. The purpose of a keylogger is to monitor and record every keystroke made by a user for various reasons, ranging from parental control to malicious activity.
Among the options provided:
- USB flash drive - A storage device, not typically used for capturing keystrokes.
- PDA - Personal Digital Assistant, an outdated type of mobile device, not specifically for capturing keystrokes.
- Smartphone - A mobile device which can have apps that may record keystrokes, but not the primary function.
- Keylogger - A specific tool designed for this purpose.
Therefore, the correct answer to the question is d) keylogger.