Assertion: In sigmoid growth curve, population finally stabilises ilself.
Reason: Finally, the death rate increases than the birlh rale.

Options

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

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that in a sigmoid growth curve, the population finally stabilizes itself. This is true because the sigmoid growth curve represents logistic growth, where the population grows rapidly at first and then stabilizes as it reaches the carrying capacity (K) of the environment.

2. **Understanding the Reason**: The reason provided states that the death rate increases more than the birth rate. This is misleading. In a sigmoid growth curve, the population stabilizes when the birth rate equals the death rate, not when the death rate exceeds the birth rate.

3. **Analyzing the Relationship**: Since the assertion is true (the population stabilizes), but the reason is false (the death rate does not necessarily exceed the birth rate for stabilization), we can conclude that the assertion and reason are not aligned.

4. **Choosing the Correct Option**: Based on the analysis:
- Option A states both assertion and reason are true and reason is the correct explanation of assertion (this is incorrect).
- Option B states both assertion and reason are true but reason is not the correct explanation (this is also incorrect).
- Option C states assertion is true but reason is false (this is correct).
- Option D states both assertion and reason are false (this is incorrect).

Thus, the correct answer is **Option C**: Assertion is true, but the reason is false.