Which type of Marine Sanitation Device (MSD) is used solely for the storage of sewage and flush water at ambient air pressure and temperature?

Correct Answer: Option C — Type III

Under 33 CFR Part 159, a Type III Marine Sanitation Device is defined as a holding tank. It does not treat sewage but is designed to store it for later discharge to a shore-side facility or into waters where such discharge is legally permitted, maintaining ambient pressure and temperature.