Final answer:
The flash point is the temperature at which a liquid can ignite, reflecting a chemical property of flammability. It is different from boiling or melting points which are physical properties.
Step-by-step explanation:
The correct answer is c. Flash point. The flash point is the minimum temperature at which a liquid produces enough vapor to ignite in the presence of an air source. This is a critical chemical property, especially when discussing the safety and handling of combustible materials. Unlike the boiling point, which is the temperature at which the vapor pressure of a liquid equals the pressure of the gas above it, the flash point does not necessarily result in a phase change but indicates potential for combustion.
a. flammability is indeed a chemical property as it describes a substance's ability to ignite or burn when exposed to an ignition source. Flammability is related to the flash point in that substances with a lower flash point have higher flammability risks. Other options like melting point, boiling point, and density are physical properties that describe the physical characteristics and behavior of matter without involving a change in its chemical composition.