Final answer:
A. Class B. If flammable liquids are on fire, you would need a Class B fire extinguisher to put out the fire.
Step-by-step explanation:
If flammable liquids are on fire, you would need a Class B fire extinguisher to put out the fire. Class B fire extinguishers are designed specifically for fires involving flammable liquids, such as gasoline, oil, and alcohol. They use extinguishing agents that work to smother the fire by creating a barrier between the fuel and the oxygen.