Which of the following concentrations of solutions of urea in water exhibits minimum freezing point depression (in $\text{ m}$)?

$1 \ kg$ of $0.75 \ m$ aqueous solution of sucrose is cooled to $-4^{\circ} C$. The amount of ice (in $g$) that will be separated out is .... . (Nearest integer)
Given: $K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1}$

If the $K_f$ value of $H_2O$ is $1.86 \ K \ kg \ mol^{-1}$,the value of $\Delta T_f$ for a $0.1 \ m$ solution of a non-volatile solute is:

Freezing point of a $4 \%$ aqueous solution of $X$ is equal to the freezing point of a $12 \%$ aqueous solution of $Y$. If the molecular weight of $X$ is $A$,then the molecular weight of $Y$ is ............. $A$.

Calculate the molar mass of a nonvolatile solute when $1.5 \ g$ of it is dissolved in $90 \ g$ of solvent,decreasing its freezing point by $0.25 \ K$. Given: $K_{f} = 1.2 \ K \ kg \ mol^{-1}$.

Which of the following formulae is used to calculate the depression in freezing point?