Assertion : Pili are nonmotile appendages of bacteria.
Reason : Pili take part in conjugation.

Options

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

Explanation

To analyze the given assertion and reason, we can break down the information step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Pili are nonmotile appendages of bacteria."
- This means that pili do not contribute to the movement of bacteria. Instead, they serve other functions.

2. **Understanding the Reason**:
- The reason states that "Pili take part in conjugation."
- Conjugation is a process of sexual reproduction in bacteria where genetic material is exchanged between two bacterial cells.

3. **Analyzing the Relationship**:
- While both the assertion and reason are true, we need to determine if the reason provides a valid explanation for the assertion.
- The assertion describes the nature of pili (nonmotile), while the reason describes their function (in conjugation).

4. **Conclusion**:
- Both statements are correct: pili are indeed nonmotile appendages, and they do participate in conjugation.
- However, the reason does not explain why pili are considered nonmotile; it simply states a function of pili. Therefore, the reason is not a correct explanation for the assertion.

5. **Final Answer**:
- The correct answer is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion.