Q.

Assertion: Magnetic field lines do not intersect each other.
Reason: It is impossible to have two direction of the magnetic field at a point.

1 Both assertion and reason are correct and reason is the correct explanation of assertion.  
2 Both assertion and reason are correct, but reason is not the correct explanation of assertion.  
3 Assertion is true, but reason is false.  
4 Assertion is false, but reason is true.  

Ans.

(1)

Magnetic field lines do not intersect, because it happen so then at that point two direction of magnetic field lines exist, which is not possible. Thus, both assertion and reason are correct and reason is the correct explanation of the assertion.