Assertion: Sulphur is the main constituent of several coenzymes, vitamins and ferredoxin.
Reason: Sulphur is present in two amino acids- valine and cysteine.

Options

A. If both assertio 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 "Sulphur is the main constituent of several coenzymes, vitamins, and ferredoxin."
- This is true because sulphur plays a crucial role in the structure of certain coenzymes and vitamins, such as biotin and thiamine, and is also a part of the protein ferredoxin.

2. **Understanding the Reason**:
- The reason states that "Sulphur is present in two amino acids - valine and cysteine."
- This statement is partially incorrect. While sulphur is indeed present in cysteine, it is not found in valine. Instead, sulphur is present in another amino acid called methionine.

3. **Evaluating the Relationship**:
- The assertion is true, but the reason is false. The reason does not correctly support the assertion because it incorrectly identifies the amino acids that contain sulphur.

4. **Conclusion**:
- Since the assertion is true and the reason is false, the correct option would be that the assertion is correct, but the reason is not.

### Final Answer:
- The assertion is true, and the reason is false.