Which class of fire extinguisher is used to fight a fire involving combustible cooking oils and fats in kitchens?

The correct choice for fighting a fire involving combustible cooking oils and fats in kitchens is Class K. Class K fire extinguishers are specifically designed for this type of fire, which often occurs in commercial kitchens where oils and fats are used for cooking. These extinguishers contain agents that can effectively cool and extinguish the flames without spreading the fire, which can happen if water or other extinguishing agents inappropriate for cooking oil fires are used.

Class K extinguishers utilize wet chemical agents that form a barrier between the oxygen and the fuel, effectively saponifying the oils and preventing re-ignition. This makes them the most suitable option for handling fires that result from cooking oils, unlike other classes of extinguishers that might be intended for different types of fires, such as combustibles, flammable liquids, or electrical fires.