What is the ratio of the volumes occupied by $2$ moles of $O_2$ and $3$ moles of $O_3$ at standard temperature and pressure ?

The correct option is B $1:1$
If the number of moles, temperature and pressure are fixed for both the gases, their volumes will be the same too. This is a direct consequence of Avagadro's law.
So, their ratio will $2:3$.