单项选择题
A vessel is fishing at anchor on the high seas. Which of the following day signals should she display if she has gear extending out over 150 meters horizontally from the vessel?（）.
A.A black ball in the forepart of her vessel B.A black double frustum of a cone C.A basket where best seen D.A black cone point upwards
单项选择题 A vessel being towed astern，where the length of the tow exceeds 200 meters，will exhibit （）.
单项选择题 A tug is towing three manned barges in line in fog. The first vessel of the tow should sound （）.
单项选择题 A triangular daymark would be colored（）.
