Concept:Vulcanization is the chemical treatment of rubber to improve its strength and elasticity.
Explanation:Natural rubber contains many reactive carbon-carbon double bonds, written as
C=C.
During vulcanization, sulfur atoms attack these double bonds and form cross-links between the polymer chains.
Therefore, the process involves the removal or consumption of the double bonds.
It does not involve removing a monomer, a single bond, or a whole polymer.
Removing monomers or polymers would destroy the rubber structure instead of strengthening it.
Answer:C. the double bond.