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

For $1000 \ g$ of $1,4$-dioxane,the cryoscopic constant $K_f = 4.9 \ K \ kg \ mol^{-1}$. What will be the depression in freezing point for a $0.001 \ m$ solution prepared in dioxane?

What is the molar mass (in $g \ mol^{-1}$) of a substance,which forms a $7 \%$ by mass solution in water,which freezes at $-0.93^{\circ} C$? ($K_{f}$ of $H_2O = 1.86 \ K \ kg \ mol^{-1}$)

The freezing point depression constant $(K_{f})$ of benzene is $5.12 \ K \ kg \ mol^{-1}$. The freezing point depression for the solution of molality $0.078 \ m$ containing a non-electrolyte solute in benzene is..........$K$ (rounded off up to two decimal places).

Which aqueous solution has the lowest freezing point?

Given below are two statements $:$
Statement $(I) : NaCl$ is added to the ice at $0^{\circ} C$,present in the ice cream box to lower the freezing point of the mixture,which helps in keeping the ice cream frozen.
Statement $(II) :$ On addition of $NaCl$ to ice at $0^{\circ} C$,there is a depression in freezing point.
In the light of the above statements,choose the correct answer from the options given below $:$