Which one of the following is a copolymer ?

Options

A. Buna - S
B. Polyvinyl chloride
C. Polypropylene
D. Poly - cis - isoprene

Answer

To determine which of the given options is a copolymer, we first need to understand what a copolymer is. A copolymer is a polymer that is made from two or more different types of monomers.

### Step-by-Step Solution:

1. **Identify the Options**:
We need to look at the options provided in the question. Although the options are not listed in the transcript, we can assume they include common polymers such as Buna-S, Polyvinyl chloride (PVC), Polypropylene, and Polycis isoprene.

2. **Analyze Each Polymer**:
- **Buna-S**: This is a copolymer made from two different monomers: butadiene and styrene.
- **Polyvinyl Chloride (PVC)**: This polymer is made from a single type of monomer, vinyl chloride.
- **Polypropylene**: This polymer is made from a single type of monomer, propylene.
- **Polycis Isoprene**: This polymer is made from a single type of monomer, isoprene.

3. **Determine the Copolymer**:
From the analysis:
- **Buna-S** is the only polymer made from two different monomers (butadiene and styrene).
- The other polymers (PVC, Polypropylene, and Polycis Isoprene) are made from single types of monomers.

4. **Conclusion**:
Therefore, the answer to the question "Which one of the following is a copolymer?" is **Buna-S**.

### Final Answer:
**Buna-S is a copolymer.**

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