Which aqueous solution exhibits highest boiling point?

${\mathrm{Na}}_2{\mathrm{SO}}_4$ furnishes more particles, i.e., Greater the number of solute particles in the solution, higher the elevation in boiling point. Among the given options sodium sulphate will furnishes more number of particles on dissociation,hence exhibits highest boiling point.

$∆{\mathrm{T}}_{\mathrm{b}}= {\mathrm{K}}_{\mathrm{b}}\mathrm{m} \mathrm{x} \mathrm{i}$

$∆{\mathrm{T}}_{\mathrm{b}} \mathrm{\alpha } \mathrm{i}$