$ Ergosterol is a lipid that changes to vitamins D on activation by UV light.
! Iron is a biochemical compoent of haemoglobin.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

To solve the assertion and reason question regarding ergosterol and iron, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Assertion**: The assertion states that "Ergosterol is a lipid that changes to vitamin D on activation by UV light."
- **Explanation**: Ergosterol is indeed a type of lipid found in fungi and some protozoa. When exposed to ultraviolet (UV) light, ergosterol undergoes a transformation to produce vitamin D2 (ergocalciferol).

2. **Evaluate the Reason**: The reason states that "Iron is a biochemical component of hemoglobin."
- **Explanation**: This statement is true. Hemoglobin, the protein in red blood cells responsible for oxygen transport, contains iron at its core. The iron atoms in hemoglobin bind to oxygen, allowing for its transport throughout the body.

3. **Determine the Truth of Each Statement**:
- Both the assertion and the reason are true statements.
- However, we need to check if the reason explains the assertion.

4. **Check for Relationship**:
- The assertion discusses ergosterol and its conversion to vitamin D, while the reason discusses iron's role in hemoglobin.
- There is no direct relationship between the two statements as they pertain to different biochemical processes.

5. **Select the Correct Option**:
- Since both statements are true but the reason does not explain the assertion, the correct answer is:
- **Option B**: Both assertion and reason are correct, but the reason is not the correct explanation of the assertion.

### Final Answer:
**Option B**: Both assertion and reason are correct, but reason is not the correct explanation of assertion.

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