Which of the following is NOT classified as a flammable solid?

Corrosive liquids are not classified as flammable solids because they primarily pose a risk of chemical burns and reactions rather than combustion. Flammable solids are materials that can ignite and sustain combustion, such as metal powders, certain explosives, and materials that burn rapidly. In contrast, corrosive liquids can damage organic tissue or destroy materials upon contact but do not necessarily ignite or burn like solids do. Therefore, they do not fit the category of flammable solids, highlighting the distinction in classification based on their properties and hazards.