Final answer:
Flammability is the chemical property among the options because it involves a chemical reaction where a substance undergoes combustion. The other options represent physical properties.
Step-by-step explanation:
The subject of this question concerns the chemical properties of substances as they pertain to Chemistry. Specifically, we are asked to identify which of the listed options is a chemical property. Among the given options, flammability is a chemical property because it describes a substance's ability to ignite and burn in the presence of an oxidant such as oxygen. In contrast, melting point, boiling point, and density are considered physical properties because they describe the physical characteristics and states of a substance without altering its chemical composition.