Which of the following polymers is used in paints?

Which of the following is a use of polyester fibres?

Polymer $X$ is an example of polyester and $Y$ is an example of polyamide. $X$ and $Y$ are respectively:

Orlon has which monomeric unit?

If $\bar{M}_w$ is the weight average molecular weight and $\bar{M}_n$ is the number average molecular weight of a polymer, the poly dispersity index $(PDI)$ of the polymer is given by

Buna-$N$ is a co-polymer of $1,3-$Butadiene and $\underline{X}$. What is $\underline{X}$?