Which extinguisher is most commonly used to fight a Class A fire?

For fighting a Class A fire, which primarily involves ordinary combustibles such as wood, paper, and textiles, the most effective extinguishing agents are water, foam, and dry chemical extinguishers.

Water is especially effective because it cools the burning material and removes heat from the fire, which is crucial for extinguishing flames. Foam extinguishers create a blanket over the burning material, helping to smother the fire and prevent re-ignition. Dry chemical extinguishers can interrupt the chemical reaction of combustion, making them versatile and effective for a variety of fires, including Class A.

The other options include extinguishing agents that are either less effective against Class A fires or are designed for different classes of fire. For instance, CO2 extinguishers are better suited for Class B and electrical fires due to their ability to displace oxygen rather than cool the fire. Halon is primarily effective for Class B and C fires as well. Therefore, the combination of water, foam, and dry chemical in the first option is the most appropriate choice for Class A fires.