A crew member reports that the high-pressure alarm light of a low-pressure CO2 fixed fire extinguishing system is illuminated. The most probable cause of this condition would be that __________.

Correct Answer: Option A — the tank cooling system has malfunctioned

In low-pressure CO2 systems, a high-pressure alarm light indicates tank pressure is rising abnormally, which directly points to a malfunction or failure of the dedicated refrigeration cooling system.