A copolymer consisting of randomly arranged monomer units A and B, where the sequence of A and B along the chain is statistical, is known as a:
Correct: D
Copolymers are classified based on the arrangement of their monomer units. A random copolymer is one in which the monomer units are arranged in a completely arbitrary or statistical sequence along the polymer chain. For example, -A-A-B-A-B-B-B-A-. In a block copolymer, different homopolymer blocks are linked together (e.g., -A-A-A-A-B-B-B-B-). An alternating copolymer has a regular, alternating sequence (e.g., -A-B-A-B-A-B-). A graft copolymer has side chains of one type of monomer grafted onto a main chain of another type. The description 'randomly arranged monomer units A and B, where the sequence of A and B along the chain is statistical' precisely defines a random copolymer.