单项选择题
A.the weight of the ship's structure and its machinery B.bunker and other consumable loads C.ballast loads D.all those weights，such as the weight of the bunkers，ballast，provisions and cargo
A.boss B.knuckle C.skeg D.strut
A.the reinforcement of the aft transverse watertight bulkhead B.the double bottom structure in way of the foremost cargo hold C.the introduction of a more rigorous survey regime and greater attention to operating procedures D.introduction of new and improved designs