Assertion: Overexposure to sun tans the skin in human beings.
Reason: In epidermal cells, melanin appears and saves the skin from UV rays of the sun 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.

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.

Answer

To solve the assertion-reason question, we need to evaluate both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Overexposure to sun tans the skin in human beings." This is true. When skin is exposed to sunlight, particularly UV rays, it can lead to an increase in melanin production, which causes the skin to darken or tan.

2. **Understanding the Reason**:
- The reason states that "In epidermal cells, melanin appears and saves the skin from UV rays of the sun." This is also true. Melanin is a pigment produced in the skin that provides some protection against the harmful effects of UV radiation.

3. **Evaluating the Relationship**:
- The assertion is about the effect of overexposure to sunlight (tanning of the skin), while the reason explains the role of melanin in protecting the skin from UV rays. The increase in melanin due to UV exposure is what leads to tanning, thus the reason does explain the assertion correctly.

4. **Conclusion**:
- Since both the assertion and the reason are true, and the reason correctly explains why the assertion is true, we conclude that option (a) is correct.

### Final Answer:
**a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.**

---