Which of the following aqueous solutions having same molality exhibits maximum boiling point elevation? (Assume complete dissociation)

The freezing point of a $0.05 \ m \ BaCl_2$ solution in water ($100 \%$ ionisation) is about $(K_f = 1.86 \ K \ kg \ mol^{-1})$. (in $^oC$)

Observe the following statements:
Statement-$I$: The boiling point of $0.1 \ M$ urea solution is less than that of $0.1 \ M$ $KCl$ solution.
Statement-$II$: Elevation of boiling point is inversely proportional to the molar mass of the solute for a given mass of solute dissolved in a fixed mass of solvent.
The correct answer is:

$17.4\% (W/V)$ of potassium sulphate $(mol. wt. = 174)$ is isotonic with $4\% (W/V)$ aqueous solution of $NaOH$. If $NaOH$ is $100\%$ ionised,the degree of ionisation of potassium sulphate is $.......... \%$.

$A$ $0.1 \ mol$ of a binary electrolyte undergoes complete dissociation in $250 \ g$ of a protic solvent. If the elevation in boiling point is $1.5 \ K$,the molal elevation constant $(K_b)$ is ............. $K \ kg \ mol^{-1}$.

Which of the following has the lowest freezing point?