What three elements must be present for fire to occur?

The correct answer identifies three critical elements of the fire triangle: fuel, oxygen, and heat.

Fuel refers to any combustible material—this could be solid, liquid, or gas—that can ignite and sustain combustion. Oxygen is essential for the combustion process since fire requires a sufficient amount of oxygen to maintain its reaction. Heat serves to initiate and continue the combustion process, raising the temperature of the fuel to its ignition point.

When any one of these three elements is missing, a fire cannot start or be sustained. Understanding this concept is crucial for both fire prevention and firefighting strategies, as removing any component can help extinguish an existing fire or prevent a fire from starting in the first place.

The other options may reference related components but do not encompass the essential elements of the fire triangle in the proper context needed for understanding fire dynamics. For instance, the third option introduces an "ignition source," which is critical for initiating combustion. However, it does not align strictly with the established components of the fire triangle, which focuses on fuel, oxygen, and heat as the primary elements necessary for fire.