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

Question

$\begin{array}{1 1} (a)\;\text{16 g of $O_2$ and 14 g of $N_2$} \\(b)\;\text{8 g of $O_2$ and 22 g of $CO_2$} \\ \text{(c) 28 g of $N_2$ and 22 g of $CO_2$}\\ \text{(d) 32 g of $O_2$ and 32 g of $N_2$ } \end{array}$