Which of the following is classified as a power source?

A battery or generator is classified as a power source because it provides electrical energy for the functioning of a circuit. Batteries store chemical energy and convert it into electrical energy when connected to a circuit, while generators convert mechanical energy into electrical energy. Both components are essential for supplying the necessary voltage and current to operate electrical devices and systems. This distinction is important as it highlights the role of power sources in establishing electrical flow, enabling all other components in a circuit to perform their intended functions.

The other options represent components with different roles within an electrical system. A fuse is a protective device that prevents overcurrent by melting and breaking the circuit, while a circuit breaker serves a similar function but can be reset after tripping. A resistor is a passive component used to limit current flow and divide voltage, but it does not provide power itself. Therefore, the characteristic of supplying electrical energy clearly identifies the battery or generator as the correct answer.