What three factors determine how a fire develops?

The correct choice highlights critical aspects that influence fire development: fuel properties, ventilation, and heat conservation.

Understanding fire development starts with fuel properties, which relate to the type and characteristics of materials that can ignite and burn. Different fuels have varied ignition temperatures, combustion rates, and energy outputs, all of which significantly affect how a fire starts and spreads.

Ventilation is equally crucial, as it determines the amount of oxygen available for combustion. Adequate ventilation can enhance fire intensity by increasing airflow, which may lead to a more vigorous fire, while restricted ventilation can starve a fire of oxygen, affecting its development and behavior.

Heat conservation refers to how effectively heat generated by a fire is retained in a space. This can influence the temperature of surrounding materials, potentially leading to ignition of adjacent combustibles. Understanding how heat can be contained or lost in a space helps predict the progression of a fire.

While the other options mention elements involved in fire dynamics, they do not encompass the comprehensive factors that together directly influence fire development.