Which of the following describes intrinsically safe equipment?

Correct Answer: Option D — an electrical circuit in which a spark is incapable of causing the ignition of a given explosive mixture

Intrinsically safe equipment is designed to limit electrical and thermal energy to levels incapable of igniting a specific hazardous atmospheric mixture. This is achieved by restricting current and voltage, ensuring that even under fault conditions, no spark or heat is sufficient to cause an explosion in a hazardous area.