Which among the following has the highest volatility ?

 Volatile nature of a compound depends on the force of attraction between the molecules in the compound. As the force of attraction increases the compound becomes less volatile.
Among group 16 elements as we move from top to bottom volatile nature decreases. This is because as the size of the atom increases the van der Waal forces also increases.
But ${\mathrm{H}}_2\mathrm{O}$ is least volatile due to strong intermolecular hydrogen bonding.
So, ${\mathrm{H}}_2 \mathrm{S}$ is the most volatile.