Assertion : Regulator and operator genes are not associated with contitutive genes.
Reason : Constitutive genes need not be repressed.

Options

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

Explanation

To analyze the given question, we need to evaluate both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding Constitutive Genes**:
- Constitutive genes are genes that are continuously expressed and transcribed. They are not subject to regulation and are always active in the cell.

2. **Role of Regulator and Operator Genes**:
- Regulator genes produce repressor proteins that can bind to operator genes. This binding can inhibit the transcription of adjacent genes in an operon, effectively stopping their expression.
- Since constitutive genes are always active, they do not require regulation by repressor proteins or operator genes.

3. **Evaluating the Assertion**:
- The assertion states that "Regulator and operator genes are not associated with constitutive genes." This is true because constitutive genes are always expressed and do not need the regulatory mechanisms that involve these genes.

4. **Evaluating the Reason**:
- The reason states that "Constitutive genes need not be repressed." This is also true because the very nature of constitutive genes is that they are always active and do not require repression.

5. **Conclusion**:
- Both the assertion and the reason are correct. Furthermore, the reason provided explains the assertion accurately. Therefore, the correct answer to the question is that both the assertion and reason are true, and the reason supports the assertion.

### Final Answer:
Both the assertion and the reason are correct, and the reason explains the assertion.

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