What should you do when the alarm bell on a self-contained breathing apparatus sounds?

Correct Answer: Option A — Immediately evacuate the contaminated area.

The low-pressure alarm on a Self-Contained Breathing Apparatus (SCBA) indicates that the air supply has reached the reserve threshold. Per standard safety protocols, the wearer must immediately evacuate the hazardous atmosphere to a safe area before the air supply is completely exhausted, ensuring personal safety during firefighting operations.