According to the 33 CFR regulations pertaining to the Oil Record Book, how long must the Oil Record Book be maintained on board those vessels for which the regulations apply?

Correct Answer: Option C — 3 years at a minimum.

Per 33 CFR 151.25(h), the Oil Record Book must be maintained on board for a minimum of three years after the last entry has been made. This duration ensures that records are available for inspection by port state control or Coast Guard officials during routine vessel examinations.