Of the following,which one is classified as a polyester polymer?

$A$ polymer sample contains $10$ molecules each with molecular mass $5,000$ and $5$ molecules each with molecular mass $50,000$. The number average molecular mass of the polymer sample is

Which of the following pairs is $NOT$ correctly matched?

$Buna-S$ is a polymer of .......

Given below are two statements $:$
Statement $I :$ Wet cotton clothes made of cellulose$-based$ carbohydrate take a comparatively longer time to dry than wet nylon polymer$-based$ clothes.
Statement $II :$ Intermolecular hydrogen bonding with water molecules is more in nylon$-based$ clothes than in the case of cotton clothes.
In the light of the above statements,choose the correct answer from the options given below $:$

Which polymer is used for making magnetic recording tapes?