Which raw material is used in the preparation of $Nylon-6,6$?

Which among the following polymers is obtained by ring opening polymerization process?

Which of the following monomers undergoes polymerization to form Neoprene?

The formation of which of the following polymers involves a hydrolysis reaction?

Among $(I)-(IV)$,the compound that does not undergo polymerisation under radical initiation is:

The correct functional group $X$ and the reagent/reaction conditions $Y$ in the following scheme are:
$X-(CH_2)_4-X \xrightarrow{Y} \text{condensation polymer}$
$(i) \text{ with } HOOC-(CH_2)_4-COOH / \text{heat}$
$(A) X = COOCH_3, Y = H_2 / Ni / \text{heat}$
$(B) X = CONH_2, Y = H_2 / Ni / \text{heat}$
$(C) X = CONH_2, Y = Br_2 / NaOH$
$(D) X = CN, Y = H_2 / Ni / \text{heat}$