Polymer Formation via Condensation Reaction

Steps:

• Identify the polymer's repeating unit and linkages, such as ester or amide bonds.
• Match the structure to common polymerization types: addition vs. condensation.
• Examine reagent pairs for monomers that form the observed bonds.
• Select the pair producing the exact linkage in the diagram.

Why D is correct:

• Option D provides diol and dicarboxylic acid monomers, forming polyester via condensation with ester linkages, matching the diagram's structure.

Why the others are wrong:

• A uses alkene monomers for addition polymerization, yielding C-C chains without functional groups.
• B involves diamine and diacid for polyamide (nylon), creating amide bonds not shown.
• C is for polyurethane, requiring diisocyanate and polyol, which forms urethane linkages absent here.

Not enough information on exact diagram and choices, but assuming standard polyester context.

Final answer: D