Assertion : If gravitational potential at some point is zero, then gravitational field strength at that point will also be zero.
Reason : Except at infinity gravitational potential due to a system of point masses at some finite distance can't be zero.

Options

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

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understanding the Assertion
The assertion states: "If gravitational potential at some point is zero, then gravitational field strength at that point will also be zero."

- Gravitational potential (V) is defined as the work done per unit mass in bringing a mass from infinity to that point.
- The gravitational field strength (E) is defined as the negative gradient of the gravitational potential, mathematically expressed as:

\[ E = -\frac{dV}{dr} \]

- Just because the gravitational potential is zero does not imply that the gravitational field strength is also zero. The field strength can still be non-zero if the potential changes with distance.

### Conclusion for Assertion
Thus, the assertion is **false**.

### Step 2: Understanding the Reason
The reason states: "Except at infinity, gravitational potential due to a system of point masses at some finite distance can't be zero."

- Gravitational potential due to point masses is always negative or zero at infinity.
- Since gravitational potential is a summation of contributions from all point masses, and since each contribution is negative (due to the attractive nature of gravity), the total potential cannot be zero at any finite distance.

### Conclusion for Reason
Thus, the reason is **true**.

### Final Conclusion
- The assertion is false, and the reason is true. Therefore, the correct answer is that the assertion does not follow from the reason.

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