单项选择题
A.Whether the fire is in machinery or passenger spaces
B.Danger of shock to personnel
C.The amount of toxic fumes created by the extinguisher
D.Maintaining electrical power
单项选择题 What is the most important characteristic of the extinguishing agent in fighting a class C fire?（）
单项选择题 What is required in addition to the heat，fuel，and oxygen of the fire triangle to have a fire?（）
单项选择题 What is NOT listed on the metallic name plate required to be attached to hand portable fire extinguishers?（）