Which of the following best defines "fire tetrahedron"?

The fire tetrahedron is a model that illustrates the four essential elements required for fire to occur. These four components are heat, fuel, oxygen, and a chemical chain reaction. Understanding the fire tetrahedron helps firefighters and emergency responders recognize that removing any one of these elements will extinguish a fire. This model expands upon the traditional fire triangle, which only included heat, fuel, and oxygen, by adding the chemical reaction component to emphasize the complexity of fire behavior and the combustion process.

The other options do not accurately reflect the concept of the fire tetrahedron. For example, describing it as a method of firefighting does not capture its role in understanding fire dynamics. Similarly, a heat-resistant material and a fire sprinkler system design are unrelated to the foundational elements of fire that comprise the tetrahedron. Thus, the definition as a model representing the elements of fire is indeed the most accurate choice.