Which protection mechanism interrupts power during a fault condition?

The correct choice is that all of the options provided perform the function of interrupting power during a fault condition, but each serves a specific purpose and context.

A fuse is a safety device designed to interrupt the electrical circuit when the current exceeds a certain level. It contains a thin wire that melts and breaks the circuit when excessive current flows, preventing potential damage or fire.

A circuit breaker serves a similar function but can be reset after it trips. It automatically disconnects the power supply in the event of an overload or short circuit, providing protection without the need for a replacement, as is necessary with a blown fuse.

A Ground Fault Circuit Interrupter (GFCI) specifically protects against ground faults, which occur when electrical current strays from its intended path. It rapidly cuts off power if it detects an imbalance between incoming and outgoing current, thus preventing electrical shocks.

Each of these devices plays a critical role in ensuring safety by interrupting power under different fault conditions, making the answer that all of these protect against electrical faults valid and comprehensive.