Ring-Opening Metathesis Polymerization of Cyclohexene

Steps:

• Cyclohexene is a cyclic alkene; addition polymerization occurs via ring-opening metathesis (ROMP).
• The double bond breaks, opening the ring to form a linear chain.
• The repeating unit is -(CH₂)₄-CH=CH-, connecting at the original double bond carbons.
• A polymer section shows two or more such units linked, preserving the double bond in the chain.

Why C is correct:

• C depicts the accurate repeating unit from ROMP, where the six-carbon ring opens to a chain with internal double bonds, per the mechanism of olefin metathesis.

Why the others are wrong:

• A shows intact rings without opening, violating addition across the double bond.
• B has incorrect connectivity, forming branched structures instead of linear chains.
• D retains the cyclic monomer without polymerization links.

Final answer: C