What characteristic defines a combustible liquid?

A combustible liquid is specifically defined by its flash point, which is the lowest temperature at which its vapors can ignite when exposed to a spark or flame. The defining characteristic of a combustible liquid is that it has a flash point at or above 100°F (37.8°C) and below 200°F (93.3°C). This range indicates that the liquid can produce enough vapor at elevated temperatures to create a flammable mixture with air.

Understanding this definition helps in recognizing the behavior of different liquids in fire situations. Liquids with flash points below 100°F are classified as flammable liquids, while those that fall in the defined range of 100°F to below 200°F are considered combustible. This distinction is crucial for safety protocols and handling procedures, especially in contexts such as industrial environments or during fire investigations.

Other options do not accurately capture the essential aspect of what defines a combustible liquid, either overstating or misrepresenting its characteristics. Therefore, the correct understanding of a combustible liquid fundamentally relies on its flash point classification as indicated in the correct answer.