Answer the following question given this paragraph: 

A circuit breaker is a switch that automatically opens a circuit if too much current flows through it. This could happen if too many electric devices are plugged into the circuit or if there is an electric short. Once the problem is resolved, the circuit breaker can be switched back on to close the circuit. Circuit breakers are generally found in a breaker box that controls all the circuits in a building.


Q: What type of switch automatically opens a circuit if too much current flows through it?

 Choices:

- toggle switch

- regulator switch

- kill switch

- circuit breaker

A:
circuit breaker
