Assertion : Miller used four gases-methane, oxygen, hydrogen and water vapour for formation of simple organic compounds.
Reason : He prepared some amino acids in his apparatus.

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 assertion
C. If the assertion is true but the reason is false
D. If the assertion is false but reason is true

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that Miller used four gases: methane, oxygen, hydrogen, and water vapor for the formation of simple organic compounds.

2. **Evaluating the Gases Used**: In reality, Miller did not use oxygen in his experiment. The gases he used were methane (CH₄), ammonia (NH₃), hydrogen (H₂), and water vapor (H₂O). Oxygen was not present in the early Earth's atmosphere, as it would react with other components and not remain free.

3. **Understanding the Reason**: The reason states that Miller prepared some amino acids in his apparatus. This is true as Miller's experiment did lead to the formation of amino acids, which are the building blocks of proteins.

4. **Conclusion on Assertion and Reason**: Since the assertion is incorrect (as it includes oxygen which was not part of the early atmosphere), but the reason is correct (Miller did produce amino acids), we can conclude that the assertion is false while the reason is true.

5. **Final Answer**: Therefore, the correct answer is that the assertion is false, but the reason is true.