Assertion:When all the three types of cones are stimulated equally, a mosaic of red, green and blue lights is produced.
Reason:cones are responsible for twilight or scotopic vision.

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 solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that when all three types of cones (red, green, and blue) are stimulated equally, a mosaic of red, green, and blue lights is produced.
- In reality, when these cones are stimulated equally, the result is the perception of white light, not a mosaic of colors. This is due to the additive color mixing principle.

2. **Understanding the Reason**:
- The reason states that cones are responsible for twilight or scotopic vision.
- This is incorrect because scotopic vision (vision in low light) is primarily the function of rods, not cones. Cones are responsible for color vision and function best in bright light.

3. **Evaluating the Truth of the Statements**:
- Since the assertion is false (it describes the outcome incorrectly) and the reason is also false (it misattributes the function of cones), we conclude that both statements are incorrect.

4. **Final Conclusion**:
- Therefore, the correct answer is that both the assertion and the reason are false.

### Final Answer:
Both assertion and reason are false.

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