請依下文回答第 51 題至第 55 題       The unit is designed for 51  in water depths of up to 250 feet. The unit is also designed for ocean  52  ,afloat on its own hull with its legs intact and fully raised so that the spud can tip is 12.38 feet below thebottom of the hull. The lightweight is the condition of the unit before loading  53  , fuel, water, orstores. For the Coastal Driller, the lightweight  54  the basic hull weight and the fixed weight. Thefixed weight is that which is permanently attached to the unit, which includes a portion that is  55  anda portion that can be moved.

【題組】51
(A) coordination
(B) ordination
(C) cooperation
(D) operation