THe qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solution of $\mathrm{KCl}, \mathrm{CH}_3 \mathrm{OH}$ and $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_{11} \mathrm{OSO}_3-\mathrm{Na}^{+}$ at room temperature. The correct assignment of the sketches is