[A]: Plasmids are double .stranded extra chromosomal DNA.
[R]: Plasmids are found in Prokaryotic cells.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To analyze the statements given in the question, we need to evaluate both the assertion (A) and the reason (R) separately.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Plasmids are double-stranded extra-chromosomal DNA."
- This is true. Plasmids are indeed small, circular, double-stranded DNA molecules that exist independently of chromosomal DNA in cells.

2. **Understanding the Reason (R)**:
- The reason states that "Plasmids are found in prokaryotic cells."
- This is also true. Plasmids are commonly found in prokaryotic cells, such as bacteria, where they can replicate independently of the chromosomal DNA.

3. **Evaluating the Relationship Between A and R**:
- While both statements are true, the assertion does not provide a correct explanation for the reason. The assertion describes the nature of plasmids, while the reason describes where they are found. The assertion does not explain why plasmids are found in prokaryotic cells.

4. **Conclusion**:
- Both the assertion and the reason are true, but the assertion is not the correct explanation for the reason. Therefore, the final answer is that both statements are true, but A is not a correct explanation of R.

### Final Answer:
- **Both A and R are true, but A is not the correct explanation for R.**