Question 1000 Deck General

The correct answer is C) 90%. According to the regulations for inert gas systems on ships, the high pressure alarm in the main vapor collection line must be set to activate at a pressure corresponding to 90% of the lowest relief valve setting. This ensures that the alarm will sound before the pressure reaches the relief valve setting, allowing the crew to take corrective action and prevent the system from reaching the maximum allowable pressure. The other options are incorrect because 70% (A) and 80% (B) are below the required 90% threshold, while 95% (D) is above the requirement.