Which of the following has number of molecules present equal to those present in 16 grams of oxygen

$\mathrm{moles}=\frac{\mathrm{given} \mathrm{mass}}{\mathrm{molecular} \mathrm{mass}}$

Moles of oxygen present in 16grams = $\frac{16}{32}=0.5$

Similarly, 32g of $S{O}_2$ contains 0.5 moles.

Hence the correct option is (B).