单项选择题 Vertically below the deckline is a circle whose outside diameter is 300mm.It is called the（）.

单项选择题 Right at the top is（）It is 300 mm long and 25 mm wide with its upper edgs in line with the uppermost continuous watertight deck.

单项选择题 （）is from baseline to top of the upper deck breadth at the ship’s side amidships.