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

Question

( A ) $\frac{5}{8}$
( B ) $\frac{5}{4}$
( C ) $\frac{4}{5}$
( D ) $\frac{4}{7}$