According to OSHA, what is the minimum fire extinguisher rating required for refueling trucks handling flammable materials?

The correct answer focuses on the minimum fire extinguisher rating needed for situations involving flammable materials, particularly when refueling trucks. The rating of 20-B:C indicates that the extinguisher is specifically designed to handle large volumes of flammable liquids, such as gasoline or oil, and can effectively combat fires that may arise in these scenarios.

A rating of 20-B:C means that the extinguisher has been tested and proven to put out fires involving flammable liquids up to a certain square footage, specifically 20 square feet. The inclusion of the "C" in the rating signifies that it is also suitable for use on electrical fires, making it versatile for the dual hazards present when dealing with refueling operations.

The other ratings would not provide the adequate level of protection required in this hazardous context. A fire extinguisher with a lower rating might not have the capacity to handle fires involving larger quantities of flammable materials, thus emphasizing the importance of having at least a 20-B:C rated extinguisher readily available in these environments.