Step 1: Recall the definition of Buna-S.
Buna-S is a synthetic rubber made by polymerizing butadiene with styrene.
Step 2: Verify options.
- (A) Iso-butadiene: Not correct.
- (B) Styrene and butane: Incorrect, it uses butadiene not butane.
- (C) Butadiene and styrene: Correct definition of Buna-S.
- (D) Acrylonitrile, butadiene and styrene: That forms ABS polymer, not Buna-S.
Step 3: Conclusion.
The correct answer is (C) Butadiene and styrene.