Which of the following polymers is used to obtain rubber belts?

Rayon yarns are obtained from

Arrange the following in decreasing order of their intermolecular forces:
$(a)$ Nylon $6,6$
$(b)$ Buna-$S$
$(c)$ Polyethene

Monomer units of $Dacron$ polymer are :

Given below are two statements,one is Assertion $(A)$ and the other is Reason $(R).$
Assertion $(A):$ Natural rubber is a linear polymer of isoprene called cis-polyisoprene with elastic properties.
Reason $(R):$ The cis-polyisoprene molecules consist of various chains held together by strong polar interactions with a coiled structure.
In the light of the above statements,choose the correct one from the options given below:

Which of the following is an example of a thermosetting polymer?