What term indicates a curvature of the decks in a longitudinal direction?（）

A.The requirement for through-ventilation
B.The corrosion some types of coal will cause to the ship
C.Spontaneous heating
D.Generation of methane gas

A.Shifting cargo
B.Moving cargo
C.Removing cargo
D.Trimming cargo

A.centerline system of framing
B.isometric system of framing
C.longitudinal system of framing
D.transverse system of framing