Assertion (A): Magnetic field lines never intersect.
Reason (R): At a particular point magnetic field has only one direction.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is NOT the correct explanation of A
C. A is true but R is false.
D. A is false and R is true

Explanation

To solve the question regarding the assertion and reason about magnetic field lines, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Magnetic field lines never intersect."
- This means that at any point in space, there cannot be two magnetic field lines crossing each other.

2. **Understanding the Reason (R)**:
- The reason states that "At a particular point, the magnetic field has only one direction."
- This implies that if you place a magnetic compass at any point in a magnetic field, the compass will point in a single direction, which indicates the direction of the magnetic field at that point.

3. **Analyzing the Assertion**:
- If magnetic field lines were to intersect, it would mean that at the point of intersection, there would be two different directions of the magnetic field.
- This is not possible because a magnetic field at a point can only have one direction. Therefore, the assertion is true.

4. **Analyzing the Reason**:
- The reason explains why the assertion is true. Since the magnetic field has only one direction at any point, it follows logically that the field lines cannot intersect.
- Thus, the reason is also true.

5. **Conclusion**:
- Since both the assertion and the reason are true, and the reason provides a correct explanation for the assertion, we can conclude that the correct answer is that both statements are true and the reason is the correct explanation of the assertion.

### Final Answer:
- Both Assertion (A) and Reason (R) are true, and the reason is the correct explanation of the assertion.

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