The solution with highest vapour pressure of the following is

 $$\begin{gathered} \mathrm{Effective} \mathrm{concentrations}; \\ 0.2\mathrm{m} \mathrm{sucrose}(0.2\mathrm{m}\times 1); \\ 0.15\mathrm{m} \mathrm{NaCl}(0.15\mathrm{m}\times 2); \\ 0.125\mathrm{m} {\mathrm{Na}}_2{\mathrm{SO}}_4(0.125\mathrm{m}\times 3); \\ 0.3\mathrm{m} \mathrm{urea} (0.3\mathrm{m}\times 1); \\ \mathrm{LVP} \propto \mathrm{molality}; \\ \mathrm{VP} \mathrm{of} 3<2=4<1 \end{gathered}$$