An insulating rod of length $$\ell$$ carries a charge q distributed uniformly all over its length. The rod is pivoted at its midpoint and is rotated at a frequency f (in Hz) about an axis perpendicular to the rod passing through the point at the pivot. The magnetic moment of the system is

A

$$\frac{1}{6}\pi q f \ell^2$$

B

$$\frac{1}{3}\pi q f \ell^2$$

C

$$\pi q f \ell^2$$

D

$$\frac{1}{12}\pi q f \ell^2$$