Amongst ${\mathrm{H}}_2\mathrm{O}, {\mathrm{H}}_2\mathrm{S}, \mathrm{and} {\mathrm{H}}_2\mathrm{Se}, {\mathrm{H}}_2\mathrm{Te},$the one with the highest boiling point is

In a group the electro negativity is gradually decreases from top to bottom.  So, the hydrogen bonding ability will also decreased for the hydrides of elements in a group from top to bottom. Therefore, in given all compounds, ${\mathrm{H}}_2\mathrm{O}$ has the highest boiling point than the remaining molecules ${\mathrm{H}}_2\mathrm{O}, {\mathrm{H}}_2\mathrm{S}, \mathrm{and} {\mathrm{H}}_2\mathrm{Se}, {\mathrm{H}}_2\mathrm{Te},$