The process that occurs when heat is generated by a chemical reaction within a substance and continues to a point of ignition is known as __________.

Correct Answer: Option A — spontaneous combustion

Spontaneous combustion occurs when a substance undergoes internal chemical oxidation, generating heat faster than it can dissipate. If the temperature reaches the material's ignition point, it will burst into flames without an external spark. This is a significant risk with oily rags or certain chemical cargoes in storage.