Among cellulose, polyvinyl chloride, nylon and natural rubber, the polymer in which the inter-molecular force of attraction is weakest is:

Cis1,4-polyisoprene is what makes up natural rubber. It possesses elastic characteristics, long flexible chains, and weak intermolecular forces.
Only C and H atoms can be found in natural rubber. As a result, it has weak van der Waals forces of attraction and non-polar C–H bonds.
Contrarily, C, H, and heteroatoms are present in cellulose, polyvinyl chloride (PVC), and nylon (Cl, N or O). They thus have polar linkages and interactions between dipoles.
The polymer in which intermolecular forces of attraction are the weakest is natural rubber, which is distinguished from cellulose, polyvinyl chloride (PVC), nylon, and natural rubber.
As a result, choice C is accurate.