A circular shaft subjected to torsion undergoesa twist of $$1^\circ$$ in a length of 120 cm. If the maximum shear stress inducedis limited to 1000kg/cm$$^2$$ and if modulus of rigidity $$G = 0.8 * 10^6 Kg/cm^2$$, then the radius of the shaft should be

A

$$\frac{\pi}{8}$$ cm

B

$$\frac{\pi}{27}$$ cm

C

$$\frac{18}{\pi}$$ cm

D

$$\frac{27}{\pi}$$ cm