Assertion: The minimum number of non-coplanar Vectors whose sum can be zero, is four
Reason: The resultant of two vectors of unequal magnitude can be zero.

Options

A. If both assertion 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 aseertion and reason are false.

Explanation

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

### Step 1: Analyze the Assertion
The assertion states that the minimum number of non-coplanar vectors whose sum can be zero is four.

- **Understanding Non-Coplanar Vectors**: Non-coplanar vectors are vectors that do not lie in the same plane. For the sum of vectors to be zero, they must balance each other out in three-dimensional space.

- **Example with Four Vectors**: Consider four vectors A, B, C, and D. If we arrange them in such a way that they form a closed tetrahedron, their vector sum can be zero. For instance:
- Vector A can point in one direction.
- Vector B can point in a different direction.
- Vector C can point in a third direction.
- Vector D can be directed such that it balances out the other three vectors.

Thus, the assertion is **true**.

### Step 2: Analyze the Reason
The reason states that the resultant of two vectors of unequal magnitude can be zero.

- **Understanding Resultant of Two Vectors**: The resultant of two vectors can only be zero if they are equal in magnitude and opposite in direction. If two vectors have unequal magnitudes, their resultant cannot be zero.

- **Conclusion on Reason**: Since the reason provided is incorrect, it is **false**.

### Final Conclusion
- The assertion is true, and the reason is false. Therefore, the correct answer is that the assertion is true, but the reason is false.

### Summary of the Solution
- **Assertion**: True (Minimum number of non-coplanar vectors whose sum can be zero is four).
- **Reason**: False (The resultant of two vectors of unequal magnitude cannot be zero).