The natural frequency of free torsional vibrations of a shaft is equal to (where q = Torsional stiffness of the shaft and $$I$$ = Mass moment of inertia of the disc attached at the end of a shaft)

A. $$2\pi \sqrt {\frac{{\text{q}}}{I}} $$

B. $$2\pi \sqrt {{\text{q}}I} $$

C. $$\frac{1}{{2\pi }}\sqrt {\frac{{\text{q}}}{I}} $$

D. $$\frac{1}{{2\pi }}$$

Answer: Option C