On board small passenger vessels, storage batteries containing an electrolyte must be set in trays constructed of __________.

Correct Answer: Option A — a material resistant to damage by the electrolyte

46 CFR 183.340 mandates that storage batteries must be secured in trays constructed of a material resistant to electrolyte damage, typically lead or heavy-duty plastic. This prevents the corrosive acid from compromising the vessel's structure or electrical integrity in the event of a spill or leakage.