A sphere and a cube having equal surface area are made of the same material. The two are heated to the same temperature and kept in identical surrounding. The ratio of their initial rates of cooling is

A

$$1 \colon 1$$

B

$$\sqrt{\frac{\pi}{2}} \colon 1$$

C

$$\sqrt{\frac{\pi}{3}} \colon 1$$

D

$$\sqrt{\frac{\pi}{6}} \colon 1$$