Q.Amongst the following, identify a copolymer.

Polymers can be classified by how many distinct kinds of monomer contribute to their repeating units. A homopolymer contains only one type of repeating unit, usually (though not always) formed from a single monomer -- polythene, polypropene, polyacrylonitrile, Nylon 6 and Nylon 6,6 are all homopolymers; Nylon 6,6 counts as a homopolymer even though it starts from two different small molecules (hexamethylenediamine and adipic acid) because those two first combine into a single salt, which is the true repeating monomer unit that then condenses further. A copolymer, by contrast, contains two or more distinct types of repeating unit, formed by polymerizing two or more different monomers together in each other's presence, with the different monomer-derived units randomly sequenced along the chain -- Buna-S (from butadiene and styrene) and Buna-N (from butadiene and acrylonitrile …