The natural frequency of free torsional vibrations of a shaft with torsional stiffness q and I is the mass moment of inertia of the disc attached to the end of the shaft is

A

$$2 \pi \times \sqrt{\frac{q}{I}}$$

B

$$2 \pi \sqrt{qI}$$

C

$$\frac{1}{2\pi} \times \sqrt{\frac{q}{I}}$$

D

$$\frac{1}{2\pi} \times \sqrt{qI}$$