According to Graham's law , at a given temperature , the ratio of rates of diffusion $\large\frac{r_A}{r_B}$ of gases A and B is given by:

Question

$\begin {array} {1 1} (a)\;(\large\frac{P_A}{P_B})(\large\frac{M_A}{M_B})^{\frac{1}{2}}\\(b)\;(\large\frac{M_A}{M_B})(\large\frac{P_A}{P_B})^{\frac{1}{2}}\\(c)\;(\large\frac{P_A}{P_B})(\large\frac{M_B}{M_A})^{\frac{1}{2}}\\(d)\;(\large\frac{M_A}{M_B})(\large\frac{P_B}{P_A})^{\frac{1}{2}} \end {array}$