Which of the following is an example of copolymer?

Options

A. Buna-`S`
B. `PAN`
C. polythene
D. `PTFE`

Answer

To determine which of the given options is an example of a copolymer, we need to understand the definition of a copolymer and analyze each option provided.

### Step-by-Step Solution:

1. **Definition of Copolymer**: A copolymer is a polymer that is made from two different types of monomeric units. This means that at least two different monomers are involved in its formation.

2. **Analyzing the Options**:
- **Option A: BUNAS**: This is a copolymer made from 1,3-butadiene and styrene. Since it is formed from two different monomers, it qualifies as a copolymer.
- **Option B: PAN (Polyacrylonitrile)**: This polymer is made from acrylonitrile only, which means it is formed from a single type of monomer. Therefore, it is not a copolymer.
- **Option C: Polythene**: This polymer is made from ethylene (ethene) monomers only. Since it involves only one type of monomer, it is not a copolymer.
- **Option D: Polytetrafluoroethane (Teflon)**: This polymer is made from tetrafluoroethylene monomers only. Like the previous two options, it is not a copolymer as it also uses only one type of monomer.

3. **Conclusion**: After analyzing all the options, we find that only BUNAS (Option A) is a copolymer, as it is formed from two different monomers (1,3-butadiene and styrene).

### Final Answer:
**The correct answer is Option A: BUNAS.**

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