A power-driven vessel of 12 meters but less than 20 meters in length is underway at night. At what minimum height above the gunwale must her masthead light be placed?

Why C is correct

33 CFR §84.02(c) prescribes that the masthead light of a power-driven vessel of 12 meters but less than 20 meters in length shall be placed at a height above the gunwale of not less than 2.5 meters. The 5-meter minimum applies to vessels of 20 meters or more under §84.02(a)(i).