Step 1: Define ABS.
ABS (Acrylonitrile Butadiene Styrene) is a copolymer formed by polymerizing acrylonitrile, butadiene, and styrene monomers.
Step 2: Analyze the options.
- (B) ABS is classified as a copolymer, distinguishing it from homopolymers and thermosetting polymers.
- (A) ABS is not a homopolymer because its synthesis involves multiple monomers.
- (C) ABS is not a thermosetting polymer; thermosetting polymers are irreversible upon formation.
- (D) ABS is not a liquid crystal polymer.
Final Answer: \[ \boxed{\text{B) Copolymer}} \]