Which of the following best describes the Class K fire extinguishers?

Class K fire extinguishers are specifically designed for use on cooking oil and grease fires, which are common in commercial kitchens and restaurants where frying and cooking with oils are prevalent. These fires present unique challenges due to the high temperatures at which cooking oils ignite and the potential for rapid spread.

The extinguishing agents used in Class K extinguishers, typically a wet chemical agent, work by both cooling the fire and forming a barrier between the oxygen and the fuel, effectively suppressing the flames and reducing the risk of re-ignition. This makes them particularly suitable for dealing effectively with the type of fires that occur from deep fryers, grills, and other cooking appliances.

Other options reference different classes of fire extinguishers: the first one pertains to Class B extinguishers used for flammable liquids and electrical fires, the third option describes Class A extinguishers that are appropriate for general combustible materials like wood and paper, and the final one is about Class C extinguishers that address electrical fires and would not be suitable for grease fires. Therefore, option B most accurately and succinctly describes the purpose of Class K fire extinguishers.