An insulating rod of length L carries charge q distributed uniformly on it. The rod is pivoted at one end and is rotated at a frequency f about a fixed perpendicular axis. Then the magnetic dipole moment of the system is:

$\pi qfL^2$ $\frac{1}{3} \pi qfL^2$ $qfL$ $qfL^2$

$\frac{1}{3} \pi qfL^2$

The correct answer is Option (2) → $\frac{1}{3} \pi qfL^2$