When may a person 12 to 15 years old legally operate a vessel powered by a motor of 15 hp or more? a) If operating within the posted speed limit b) If they have a CPR education certificate onboard c) If supervised onboard by a person at least 18 years of age who is in possession of a California Boater Card d) If under the supervision of a person at least 18 years of age in a nearby vessel