Which of the following is $NOT$ correct for Terylene?

Buna-$N$ synthetic rubber is a copolymer of ........

Which among the following polymers is used to manufacture water pipes?

The biodegradable polymer is

Buna-$N$ synthetic rubber is a copolymer of:

Which of the following statements are correct?
$a$. Natural rubber becomes soft and sticky at high temperature.
$b$. Neoprene is a polymer of $2-$chloro$-1,3-$butadiene.
$c$. Nylon $6,6$ is a polyamide fibre.
$d$. Buna$-S$ is an example of a homopolymer.