What is the primary function of a circuit breaker?

The primary function of a circuit breaker is to prevent electrical circuits from becoming overloaded. This is accomplished through the circuit breaker's ability to interrupt the flow of electricity when it detects an overload or a fault condition, such as a short circuit. This interruption is crucial for protecting both the wiring and any connected devices from damage that can result from excessive current flow.

Maintaining power flow, converting AC to DC, and storing electrical energy are not functions of a circuit breaker. Maintaining power flow is more about the roles of conductors and switches within a circuit, while converting AC to DC is typically done by devices such as rectifiers. Energy storage is handled by capacitors and batteries, not circuit breakers. Therefore, the circuit breaker's key role is to safeguard the electrical system by cutting off the current during dangerous conditions, making option A the appropriate choice.