Charge q is uniformly spread on a thin ring of radius R. The ring rotates about its axis with a uniform frequency f Hz. The magnitude of magnetic induction at the centre of the ring is

• A. \[\frac{{{\mu }_{0}}qf}{2R}\]
• B. \[\frac{{{\mu }_{0}}q}{2f\,R}\]
• C. \[\frac{{{\mu }_{0}}q}{2\pi f\,R}\]
• D. \[\frac{{{\mu }_{0}}qf}{2\pi \,R}\]