Which component is primarily responsible for protecting a circuit from overloads?

The fuse is primarily responsible for protecting a circuit from overloads by acting as a safety device that interrupts the flow of electric current when it exceeds a certain level. When an overload occurs, the fuse melts due to the excessive heat generated by the high current, thus breaking the circuit and preventing further damage to the electrical components or potential hazards like fires. This protective function is essential in maintaining the integrity of electrical systems, ensuring that they operate safely within their specified limits.

In contrast, a switch is used to open or close a circuit, allowing or stopping the flow of current as needed, but does not provide overload protection. A resistor manages the flow of current within a circuit but does not disconnect the circuit in the event of an overload, and a capacitor stores electrical energy for short periods but does not serve a protective role against overloads. Therefore, the fuse is the correct answer because it specifically fulfills the need for overload protection in electrical circuits.