A term applied to the bottom shell plating in a double-bottom ship is（）.

A.areas where special materials are used
B.hazardous areas
C.location of emergency repair equipment
D.type and strength of materials used

A.any deck below the main deck and above the lowest deck
B.a member that gives fore-and-aft strength
C.made by placing two bulkheads a few feet apart
D.a heavy fore-and-aft beam under the deck