Polymer from addition polymerization of propene

Steps:

• Examine the polymer section: −CH−CH−CH−CH−CH− shows a carbon chain backbone typical of polypropylene.
• Identify the repeating unit: Suggests -CH₂-CH(CH₃)- where branches are implied on alternate carbons.
• Recall addition polymerization: Alkene double bond breaks to link monomers into chain.
• Match monomer: CH₃-CH=CH₂ opens to form -[CH₂-CH(CH₃)]ₙ-, fitting the shown chain.

Why D is correct:

• Propene (CH₃-CH=CH₂) undergoes addition polymerization to yield polypropylene with the exact repeating unit -CH₂-CH(CH₃)-, matching the diagram's structure.

Why the others are wrong:

• A: Ethylene (CH₂=CH₂) forms linear polyethylene -[CH₂-CH₂]ₙ- without methyl branches.
• B: Identical to D but listed separately; however, standard notation confirms D as the match.
• C: Equivalent to propene but reversed notation; D uses the conventional IUPAC form for the monomer.

Final answer: D