According to the regulations for passenger vessels, a "motor vessel" is one which is propelled by machinery other than steam and is more than __________.

Correct Answer: Option D — 65 ft. in length

Under 46 CFR, a motor vessel is defined as any vessel propelled by machinery other than steam that exceeds 65 feet in length. Vessels 65 feet or less are generally classified as motorboats. This distinction is critical for determining applicable inspection requirements, safety equipment, and manning regulations for the vessel.