The Van't Hoff factor will be highest for

$0.5 \ m$ aqueous solution of a weak acid $(HX)$ is $20 \%$ ionized. If $K_{f}$ of water is $1.86 \ K \ kg \ mol^{-1}$,the lowering in freezing point of the solution is: (in $K$)

Among the following $0.1 \ m$ aqueous solutions,which one will exhibit the lowest boiling point elevation,assuming complete ionization of the compound in solution?

$A$ solution of $CaCl_2$ is prepared by dissolving $0.0112 \ g$ of $CaCl_2$ in $1 \ kg$ of distilled water. If the molal freezing point depression constant $(K_f)$ of water is $2 \ K \ kg \ mol^{-1}$,what is the depression in the freezing point of the solution? (Assume $100\%$ ionization of $CaCl_2$)

$A$ $0.0020 \ m$ aqueous solution of an ionic compound $[Co(NH_3)_5(NO_2)]Cl$ freezes at $-0.00732 \ ^oC.$ Number of moles of ions which $1 \ mol$ of ionic compound produces on being dissolved in water will be
$(K_f = 1.86 \ ^oC/m)$

Identify the correct statement from the following.