Answer: The correct option is (b.).
Step-by-step explanation:
A path along which magnetic lines moves from north pole to south pole. The magnetic field lines shows the strength and direction of the magnetic field.
- If the magnetic lines are closer to each other that means magnetic field is strong in that region.
- If the magnetic field lines are not that much close than the strength of the magnetic field is weak.
From the given options the correct answer is option (b).