A solid sphere having mass $$m$$ and radius $$r$$ rolls down an inclined plane. Then its kinetic energy is

A

$$\tfrac{5}{7}$$ rotational and $$\tfrac{2}{7}$$ translational

B

$$\tfrac{2}{7}$$ rotational and $$\tfrac{5}{7}$$ translational

C

$$\tfrac{2}{5}$$ rotational and $$\tfrac{3}{5}$$ translational

D

$$\tfrac{1}{2}$$ rotational and $$\tfrac{1}{2}$$ translational