True/false mix: choose the single WRONG statement about common polymers and rubbers (thermoplasticity, natural origin, and copolymer/homopolymer identities).

Introduction / Context:
Accurate classification of common materials avoids design and processing mistakes. This question asks you to identify the single wrong statement in a list that mixes thermoplasticity, natural polymers, and specific polymer identities.

Given Data / Assumptions:

• Thermoplastic vs thermoset definitions are standard.
• “Protein” refers to polypeptides from natural sources.
• Neoprene = polychloroprene (synthetic).
• SBR = styrene–butadiene rubber (copolymer).

Concept / Approach:
(a) True: polystyrene softens on heating and is recyclable as a thermoplastic. (b) True: proteins are natural polymers with peptide bonds (polyamides). (c) False: neoprene is a synthetic rubber produced by addition polymerisation of chloroprene; natural rubber is cis-1,4-polyisoprene from latex. (d) True as worded: polyethylene is a homopolymer (from ethylene); SBR is a copolymer of styrene and butadiene.

Step-by-Step Solution:
Check each statement against accepted definitions.Identify (c) as the only incorrect statement.Confirm (a), (b), (d) as correct.

Verification / Alternative check:
Materials datasheets and polymer encyclopedias list neoprene under synthetic rubbers and SBR explicitly as a copolymer.

Why Other Options Are Not Wrong:
(a) and (d) align with standard classifications.(b) proteins are indeed natural polymers.

Common Pitfalls:
Confusing “natural rubber” with any rubbery material; forgetting SBR's two-monomer composition.

Final Answer:
Neoprene is a natural rubber.