The correct answer is B. Vinyl chloride.
Vinyl chloride is a chemical compound with the formula CH2=CHCl. It is a colorless, flammable gas with a characteristic sweet odor. It is used to make polyvinyl chloride (PVC), a common plastic.
Propane is a hydrocarbon with the formula C3H8. It is a colorless, odorless gas that is used as a fuel.
Styrene is a hydrocarbon with the formula C8H8. It is a colorless, flammable liquid that is used to make polystyrene, a common plastic.
Acetylene is a hydrocarbon with the formula C2H2. It is a colorless, flammable gas that is used to make a variety of chemicals, including plastics, rubber, and fibers.
PVC is obtained by the polymerization of vinyl chloride. In this process, many vinyl chloride molecules are joined together to form a long chain. This chain is then cross-linked, which makes it strong and durable. PVC is used to make a variety of products, including pipes, fittings, windows, and siding.