If the ratio of the concentration of electrons that of holes in a semiconductor is $$\dfrac{7}{5}$$ and the ratio of currents is $$\dfrac{7}{4}$$, then what is the ratio of their drift velocities?

A

$$\dfrac{4}{7}$$

B

$$\dfrac{5}{8}$$

C

$$\dfrac{4}{5}$$

D

$$\dfrac{5}{4}$$