Acrilan is a hard, horny and a high melting point material. Which of the following represents its structure :

Acrilan (also called orlon) is polyacrylonitrile (PAN), an addition polymer of acrylonitrile (vinyl cyanide), $CH_2=CH-CN$.
$n\,CH_2=CH-CN \xrightarrow{peroxide\ catalyst} [-CH_2-CH(CN)-]_n$
The strongly polar CN groups give strong intermolecular forces, which make the polymer hard, horny and high melting. It is used as a substitute for wool.
$[-CH_2-C(CH_3)(COOC_2H_5)-]_n$ is an ester polymer of the methacrylate type, $[-CH_2-CH(COOC_2H_5)-]_n$ is poly(ethyl acrylate), and $[-CH_2-CH(Cl)-]_n$ is PVC.
So the structure of acrilan is $[-CH_2-CH(CN)-]_n$.