Which of the following aqueous solutions has the highest freezing point?

Two elements $A$ and $B$ form compounds with molecular formulas $AB_2$ and $AB_4$. When $1 \ g$ of $AB_2$ is dissolved in $20 \ g$ of $C_6H_6$,the freezing point decreases by $2.3 \ K$. When $1 \ g$ of $AB_4$ is dissolved in $20 \ g$ of $C_6H_6$,the freezing point decreases by $1.3 \ K$. The molal depression constant for benzene is $5.1 \ K \ kg \ mol^{-1}$. Calculate the atomic weights of $A$ and $B$.

$1.00 \, g$ of a non-electrolyte solute dissolved in $50 \, g$ of benzene lowered the freezing point of benzene by $0.40 \, K$. The freezing point depression constant of benzene is $5.12 \, K \, kg \, mol^{-1}$. Find the molar mass of the solute.

$A$ $5\%$ solution (by mass) of cane sugar in water has a freezing point of $271 \ K$ and the freezing point of pure water is $273.15 \ K$. The freezing point of a $5\%$ solution (by mass) of glucose in water is ............. $K$.

At $T$ $(K)$,$x \ g$ of a non-volatile solid (molar mass $78 \ g \ mol^{-1}$) when added to $0.5 \ kg$ water,lowered its freezing point by $1.0^{\circ} C$. What is $x$ (in $g$)? ($K_{f}$ of water at $T$ $(K)$ = $1.86 \ K \ kg \ mol^{-1}$)

$A$ solvent freezes at $17^{\circ} C$ and it has a latent heat of fusion of $180 \ J \ g^{-1}$. The molal depression constant $(K_{f})$ of the solvent is (in $K \ kg \ mol^{-1}$):