Read the Assertion (A) and Reason (R) about the magnetic field lines of a bar magnet and choose the correct option.

• Assertion (A): Unlike electric field lines, the magnetic field lines of a bar magnet have no starting point or end point; they do not stop at the poles but continue through the magnet from S to N.
• Reason (R): Isolated magnetic poles (monopoles) are not known to exist, so a magnetic field has no sources or sinks on which its lines could begin or end.