Which of the following polymers is classified as a fibre depending on intermolecular forces?

Nylon $6,6$ is not a

Which of the following polymers is grouped in the category of elastomers?

Which one is a polymer compound?

Which of the following is not a natural polymer?

$A$ polymer contains $50$ molecules with molecular mass $5,000$, $100$ molecules with molecular mass $10,000$ and $50$ molecules with molecular mass $15,000$. Calculate the number average molecular mass. (in $,000$)