A portable foam (stored-pressure type) fire extinguisher would be most useful in combating a fire in（）.

A.gravity when the extinguisher is turned upside down
B.pressure from a small CO₂ cartridge on the extinguisher
C.air pressure from the hand pump attached to the extinguisher
D.pressure from the reaction when water is mixed with the chemical

A.there are passengers berthed on board
B.navigating in excess of eight hours
C.the vessel has substantial wood in its construction
D.there is no automatic fire-detection system installed