The correct answer is A. Surge protector.
A surge protector is a device that is designed to protect electrical devices from power surges. Power surges can be caused by a number of things, such as lightning strikes, switching on or off large appliances, and even the normal operation of some appliances. When a power surge occurs, it can cause a sudden increase in voltage that can damage or destroy electrical devices. A surge protector works by diverting the excess voltage away from the protected devices.
A UPS, or uninterruptible power supply, is a device that provides backup power to electrical devices during a power outage. A UPS does not protect against power surges.
A logic probe is a device that is used to test the logic levels of digital circuits. A logic probe does not protect against power surges.
A capacitor is a device that stores electrical energy. A capacitor does not protect against power surges.
Therefore, the correct answer is A. Surge protector.