单项选择题
A.solid materials such as wood or bales of fiber
B.flammable liquids
C.electrical equipment
D.metallic solids
单项选择题 Fittings used for towing must be（）.
单项选择题 Fire protection regulations for towing vessels require any fuel line subject to internal head pressure from fuel in the tank to（）.
单项选择题 Fire protection regulations for towing vessels require all crew members to know how to perform each of these tasks EXCEPT（）.