The correct answer is C. Isoprene.
Natural rubber is a polymer of isoprene, a five-carbon hydrocarbon. It is produced by the polymerization of isoprene monomers, which are linked together to form long chains. These chains are then twisted and folded into a spiral shape, which gives natural rubber its elasticity.
Vinyl acetate is a monomer that is used to make polyvinyl acetate, a type of plastic. Propene is a monomer that is used to make polypropylene, a type of plastic. Styrene is a monomer that is used to make polystyrene, a type of plastic.
All of these monomers are hydrocarbons, but they have different chemical structures. Isoprene is the only one of these monomers that can be used to make natural rubber.