Under Annex I (33 CFR §84.02), when a power-driven vessel of 20 meters or more carries two masthead lights, what is the minimum vertical separation required between the forward and after masthead lights?

Why B is correct

33 CFR §84.02(a)(ii) states that when two masthead lights are carried, the after one shall be at least 2 meters vertically higher than the forward one. Additionally, §84.02(b) requires that the vertical separation be sufficient so the after light appears over and separate from the forward light at 1000 meters from the stem at water level.