Final answer:
A circuit breaker is installed to protect wiring before it gets to the fuse box.
Step-by-step explanation:
A circuit breaker (option B) is installed to protect wiring before it gets to the fuse box. A circuit breaker is an automatic but restorable electric switch that interrupts excessive currents to prevent thermal hazards. It acts like an automatic switch that opens when the sustained current exceeds desired limits. Unlike a fuse, a circuit breaker can be reset and reused after it has tripped.