What would be the most probable cause for a high-pressure alarm to be activated in a low-pressure CO2 fixed fire extinguishing system?

Correct Answer: Option C — The tank cooling system has malfunctioned.

Low-pressure CO2 systems maintain liquid carbon dioxide at approximately 0°F using refrigeration units. If the cooling system malfunctions, the temperature and pressure within the storage tank rise. This triggers high-pressure alarms, alerting engineers to a potential loss of system integrity or an impending safety valve discharge.