Correct Answer - B
Nylon-6,6 is fibre , thus it has strong intermolecular forces like H-bonding. Buna-S is an elestomer, thus it has weakest intermolecular forces. Polythene is a themoplastic polymer, thus the intemoleculer forces present in polythene are in between elastomers and fibres. Thus, the order of intermolecular forces is
`B lt C lt A`