Which is better, water fire extinguisher or dry powder fire extinguisher? Where can I buy it?

I think it is best to use dry powder fire extinguishers, because fires are divided into four categories; Class A: solid fire; Class b: liquid fire; Class C: gas fire; Class d: metal fire. Most fires in the home are caused by combustible gases in electrical appliances and kitchens, while water can only put out Class A fires, and dry powder can put out Class A fires, and the operation is simple. There are two kinds of dry powder fire extinguishers, A B C and B C. Remember to buy ABC when you buy it, which can put out class III fire. You can buy it in the fire equipment store, and the price of 4KG is about 100 yuan.