The correct answer is B) smothering the burning material. Foam extinguishes a fire by creating a blanket or "smothering" effect over the burning material, cutting off the supply of oxygen that is required for combustion. The foam creates a physical barrier between the fire and the air, effectively extinguishing the flames. The other answer choices are incorrect because they do not accurately describe how foam works to put out a fire. Organic destruction, absorption, and chemical combination are not the primary mechanisms by which foam extinguishes a fire. Smothering by depriving the fire of oxygen is the key function of foam in firefighting.