The correct choice is (a) Homopolymer
For explanation: When all the monomer units in a chain are of the same type, they are called homopolymers. When a polymer is created using different types of monomers, it is a copolymer. For example, -M-M-M-M- is a homopolymer and -M1-M2-M1-M2- is a copolymer. Linear and branched polymers are types of homopolymers.