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

On complete hydrogenation,natural rubber produces

Bakelite is a cross-linked polymer of formaldehyde and :

Which of the following polymers has an ester linkage?

Ethylene on reaction with cold, dilute alkaline $KMnO_4$ at $273 \ K$ gives a compound '$P$'. This on polymerisation with which of the following gives dacron?

Given below are two statements:
Statement $I:$ Ethene at $333$ to $343 \ K$ and $6-7 \ atm$ pressure in the presence of $AlEt_3$ and $TiCl_4$ undergoes addition polymerization to give $LDP$.
Statement $II:$ Caprolactam at $533-543 \ K$ in $H_2O$ through step growth polymerizes to give Nylon-$6$.
In the light of the above Statements,choose the correct answer from the options given below: