Which one of the following pairs of gases contains the same number of molecules?

Number of molecule in each pair of given options;

(a) $\begin{array}{r}\frac{16}{32},\frac{14}{28}\end{array}$  (b) $\begin{array}{r}\frac{8}{32},\frac{22}{44}\end{array}$

(c) $\frac{28}{28},\frac{44}{44}$    (d)  $\frac{32}{44},\frac{32}{28}$

Thus, the number of molecule is same for the  pair of $16 \mathrm{g}$ of ${\mathrm{O}}_2$ and $14 \mathrm{g}$ of ${\mathrm{N}}_2$.