Which of the following samples must have molar mass greater than a mixture of $\mathrm{CO}$ and ${\mathrm{CO}}_2$?

Here;

${\mathrm{M}}_{{\mathrm{O}}_3},{\mathrm{M}}_{{\mathrm{SO}}_2}>{\mathrm{M}}_{\mathrm{CO}}$ and ${\mathrm{M}}_{{\mathrm{CO}}_2}$
Thus, the for (Mixture of ${\mathrm{O}}_3$ and ${\mathrm{SO}}_2$), molar mass greater than a mixture of $\mathrm{CO}$ and ${\mathrm{CO}}_2$.