In vulcanization, natural rubber is heated with which of the following?

Correct Answer: B. Sulfur 

Vulcanization is a chemical process in which the rubber is heated with sulfur, accelerator, and activator at 140–160°C. Vulcanization of rubber is a process of improvement of the rubber elasticity and strength by heating it in the presence of sulfur, which results in three-dimensional cross-linking of the chain rubber molecules (polyisoprene) bonded to each other by sulfur atoms.