The breakdown field for air is about $$2\times 10^{6}$$ volt/m. Therefore, the maximum charge that can be placed on a sphere of diameter 10 cm is

A

$$2.0\times 10^{-4}$$ C

B

$$5.6\times 10^{-7}$$ C

C

$$5.6\times 10^{-2}$$ C

D

$$2.0\times 10^{2}$$ C