Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths $\lambda_1 : \lambda_2$ emitted in the two cases is

Question

( A ) $\frac{20}{7}$
( B ) $\frac{7}{5}$
( C ) $\frac{27}{5}$
( D ) $\frac{27}{20}$