A passenger vessel in river service which operates in fresh water at least 6 out of every 12 months since the last dry dock examination must be dry-docked at intervals not to exceed __________.

Correct Answer: Option D — 60 months

Per 46 CFR 71.50-15, passenger vessels operating exclusively in fresh water for at least six of every twelve months since the last dry-docking may extend the interval between dry-dock examinations to 60 months, provided the vessel meets specific maintenance and inspection criteria established by the Officer in Charge, Marine Inspection.