The correct answer is (c). Polythene is not a condensation polymer.
Condensation polymers are formed by the reaction of two monomers, each of which contains at least one functional group that can react with the other monomer. The functional groups can be either hydroxyl (-OH), carboxyl (-COOH), or amino (-NH2). When the monomers react, they lose a small molecule, such as water, ammonia, or carbon dioxide. This is why condensation polymers are also called step-growth polymers.
Nylon is a condensation polymer formed from the reaction of hexamethylenediamine and adipic acid. DNA is a condensation polymer formed from the reaction of deoxyribonucleic acid and ribonucleic acid. Bakelite is a condensation polymer formed from the reaction of phenol and formaldehyde.
Polythene is a homopolymer formed from the polymerization of ethylene. It is not a condensation polymer because it is not formed from the reaction of two monomers.