Which of the following is a method to safely discharge an inductor when opening a circuit?

A field discharge resistor is a safe method to discharge an inductor when opening a circuit because it provides a controlled path for the energy stored in the inductor to dissipate safely. When an inductor is suddenly disconnected from a circuit, the collapse of the magnetic field can generate a high voltage across the inductor terminals, potentially causing arcing, damage to components, or even safety hazards. The field discharge resistor acts as a controlled load that allows the inductor's stored energy to safely convert to heat without producing high spikes in voltage.

By integrating a resistor in parallel or in series with the inductor, the energy can be gradually released, preventing sudden voltage surges. This method is particularly important in circuits where sensitive electronic components are present, as it helps maintain the integrity of the circuit and ensures safety.

Other methods, while they may seem like quick solutions, do not prioritize the controlled discharge of energy or might introduce additional risks, such as arcing or damaging components.