$R$ and $r$ are the radii of the earth and moon respectively, $\rho_e$ and $\rho_m$ are densities of earth and moon respectively . The ratio of the acceleration due to gravity on the surfaces of the moon and earth, is :

Question

( A ) $\frac{r}{R}. \frac{\rho_e}{\rho_m}$
( B ) $\frac{r}{R}. \frac{\rho_m}{\rho_e}$
( C ) $\frac{R}{r}. \frac{\rho_e}{\rho_m}$
( D ) $\frac{R}{r}. \frac{\rho_m}{\rho_e}$