单项选择题
A.cross connection line between two main fire lines B.special wrench for tightening couplings in a fire hose line C.tackle rigged to support a fire hose D.None of the above
A.proceed with fueling operation B.have helicopter move to a safer location C.wash spilled fuel away with a flood of water D.clean spilled fuel with rags
A.a gas mask certified by the Mine Safety and Health Administration B.the same self-contained breathing apparatus required with the fireman's outfit C.an oxygen breathing apparatus，provided that the device has been inspected within three years D.a portable ventilation system that will provide a complete change of air every three minutes