Nylon polymers are

The repeating unit present in Nylon $6$ is

Consider the following sequence of reactions.
$2 CH_3Cl + Si$ $\xrightarrow[573 \ K]{Cu} X$ $\xrightarrow{H_2O} Y$ $\xrightarrow{\text{Polymerization}} Z$
The repeating structural unit in $Z$ is

Match the following:

List-$I$ (Use)	List-$II$ (Substance)
$A$. Electrodes in batteries	$II$. Polyacetylene
$B$. Welding of metals	$III$. Oxyacetylene
$C$. Toys	$I$. Polypropylene

The correct answer is

Structures of some common polymers are given. Which one is not correctly presented?

Identify the addition polymer from the following: