Final answer:
Wet chemical agents are the most effective against Class-K fires, specifically designed to combat high-temperature cooking oil and grease fires by cooling and creating a barrier to prevent re-ignition. Foam-based agents are also useful, while dry chemical agents are not recommended for this class of fire.
Step-by-step explanation:
Class-K fires are a type of fire that involves combustible cooking media such as fats, oils, and greases typically found in commercial kitchens. Among the fire suppression agents listed, wet chemical agents are the most effective against Class-K fires. These agents are specifically formulated to suppress the high-temperature fires that can occur in cooking appliances and are designed to both cool the grease and create a barrier between the oxygen and the fuel to prevent re-ignition.
Fire extinguishers that contain foam-based agents are also used to fight fires involving flammable liquids. A fluorinated solution within these foam agents can spread across the burning surface and extinguish the fire by reducing the surface tension of water below that of the fuel.
Traditionally, dry chemical agents were used in fire extinguishers, but they are no longer recommended for Class-K fires due to their potential for reigniting and the damage they can cause to cooking appliances. Thus, after evaluating all options, it's clear that wet chemical agents, especially those designed for fighting Class-K fires, are the best choice.