Assertion : When two masses come closer, their gravitational potential energy decreases.
Reason : In moving attract each other.

Options

A. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.
B. If both Assertion and Reason are true but Reason is not the correct explantion of Assertion.
C. If Assertion is true, but the Reason is false.
D. If Assertion is false but the Reason is true.

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 two masses come closer, their gravitational potential energy decreases.
- The formula for gravitational potential energy (U) between two masses (m1 and m2) separated by a distance (r) is given by:
\[ U = -\frac{G m_1 m_2}{r} \]
- Here, G is the gravitational constant.

2. **Analyzing the Effect of Distance on Potential Energy**:
- As the two masses come closer, the distance (r) between them decreases.
- When r decreases, the absolute value of U (which is negative) becomes larger in magnitude (less negative).
- This indicates that the gravitational potential energy is increasing (becoming less negative), which means it is decreasing in terms of energy value.

3. **Conclusion about the Assertion**:
- Therefore, the assertion is true: When two masses come closer, their gravitational potential energy decreases.

4. **Understanding the Reason**:
- The reason states that in moving, the masses attract each other.
- This is a true statement as gravitational forces cause masses to attract each other, leading to a decrease in the distance between them.

5. **Evaluating the Relationship between Assertion and Reason**:
- While both the assertion and reason are true, the reason does not provide a correct explanation for the assertion.
- The reason describes the phenomenon of attraction but does not explain why the gravitational potential energy decreases when the masses come closer.

6. **Final Conclusion**:
- The correct option is: Both Assertion and Reason are true, but the Reason is not the correct explanation for the Assertion.

### Final Answer:
Both Assertion and Reason are true, but Reason is not the correct explanation for the Assertion.

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