$1\%$ solution of $Ca(NO_3)_2$ has a freezing point:

Molal depression constant $(K_{f})$ is dependent on

Given below are two statements $:$
Statement $(I) :$ Molal depression constant $K_{f}$ is given by $\frac{M_1 R T_f^2}{1000 \Delta H_{\text {fus }}}$,where symbols have their usual meaning. (Note: The provided formula in the prompt was corrected to the standard thermodynamic expression $K_f = \frac{M_1 R T_f^2}{\Delta H_{\text {fus }}}$).
Statement $(II) :$ $K_{f}$ for benzene is less than the $K_{f}$ for water.
In the light of the above statements,choose the most appropriate answer from the options given below $:$

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

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

The aqueous solution of urea has a freezing point of $-0.6\,^\circ C$. To prepare such a solution,how many grams of urea are needed to dissolve in $3\,kg$ of water? $(M = 60\,g\,mol^{-1}, K_{f} = 1.5\,^\circ C\,kg\,mol^{-1})$