Which of the following aqueous solutions exhibits the lowest freezing point depression, assuming complete dissociation?

If a $0.4 \text{ molal}$ solution of a nonvolatile solute in an organic solvent decreases its freezing point by $2.4 \text{ K}$, then the molal depression constant $(K_f)$ of the solvent will be:

$A$ 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 $K \ kg \ mol^{-1}$):

The freezing point of a diluted milk sample is found to be $-0.2\ ^\circ C$,while it should be $-0.5\ ^\circ C$ for pure milk. How much water has been added to pure milk to make the diluted sample?

What is the freezing point of a $1 \ molal$ aqueous solution of a non-volatile solute (in $^{\circ} C$)? $(K_{f} = 1.86 \ K \ kg \ mol^{-1}, T_{f}^{\circ} \text{ for water } = 0^{\circ} C)$

$C_{6}H_{6}$ freezes at $5.5^{\circ} C$. The temperature at which a solution of $10 \ g$ of $C_{4}H_{10}$ in $200 \ g$ of $C_{6}H_{6}$ freezes is $...... \ ^{\circ} C$. (The molal freezing point depression constant of $C_{6}H_{6}$ is $5.12 \ ^{\circ} C/m$.)