Final answer:
Acetone is a flammable liquid used as a solvent and as the primary ingredient in some nail polish removers. It is combustible, volatile, and needs to be handled with care.
Step-by-step explanation:
Acetone (nail polish remover) is a flammable liquid. This colorless solvent, known as the simplest ketone, has a wide range of uses, including as a solvent for paints, lacquers, cellulose acetate, and various other substances. Additionally, it is a major ingredient in many nail polish removers. Acetone is highly volatile and should be handled with care due to its flammability. It is important to understand that while acetone is combustible, the correct classification in the context of the question would be a flammable liquid (Option D), as it can easily catch fire at room temperature.