A spherical iron ball $$10$$ cm in radius is coated with a layer of ice of uniform thickness than melts at a rate of $$50$$ cm$$^3$$/min. When the thickness of ice is $$5$$ cm, then the rate at which the thickness of ice decreases, is

A

$$\frac{1}{36\pi}$$ cm/min

B

$$\frac{1}{18\pi}$$ cm/min

C

$$\frac{1}{54\pi}$$ cm/min

D

$$\frac{5}{6\pi}$$ cm/min