Which type of fire extinguisher is deemed most appropriate for extinguishing combustible ordinary materials?

The most appropriate type of fire extinguisher for extinguishing combustible ordinary materials, such as wood, paper, and cloth, is the Class A extinguisher. Class A extinguishers are specifically designed to combat fires involving these common materials that are categorized as ordinary combustibles. They typically contain agents like water or foam that effectively cool the burning material, removing the heat source necessary for the fire to continue.

In contrast, Class B extinguishers are intended for flammable liquids like gasoline and oil, and using them on ordinary combustibles may not be effective and could even exacerbate the situation. Class C extinguishers are designed for fires involving electrical equipment, which requires a different approach to safely extinguish without risking electric shock. Class D extinguishers are meant for combustible metals, which are not applicable to ordinary materials. Thus, the Class A fire extinguisher is specifically tailored for fighting fires fueled by ordinary combustibles, making it the correct choice in this scenario.