Which fire extinguisher class is rated specifically for kitchen cooking-oil and animal-fat fires?

Explanation

Class K extinguishers (potassium acetate or potassium citrate solution producing saponification) are designed for commercial-kitchen cooking-oil and animal-fat fires, which cannot safely be extinguished with water. Class A handles ordinary combustibles (wood, paper, cloth); Class B handles flammable liquids (gasoline, oil); Class C handles energized electrical equipment; Class D handles combustible metals (magnesium, lithium). Using the wrong class can be catastrophic — water on a grease fire causes a fireball; water on energized equipment can electrocute the operator.