What is the unit of cryoscopic constant?

Consider the given plots of vapour pressure $(VP)$ vs temperature $(T / K)$. Which amongst the following options is the correct graphical representation showing $\Delta T_f$,the depression in the freezing point of the solvent in a solution?

Mass of ethylene glycol (antifreeze) to be added to $18.6 \ kg$ of water to protect the freezing point at $-24^{\circ} C$ is . . . . . . $kg$ (Molar mass in $g \ mol^{-1}$ for ethylene glycol $= 62$,$K_{f}$ of water $= 1.86 \ K \ kg \ mol^{-1}$)

How does sprinkling of salt help in clearing the snow-covered roads in hilly areas? Explain the phenomenon involved in the process.

$K_{f}$ (water) $= 1.86 \ K \ kg \ mol^{-1}$. The temperature at which ice begins to separate from a mixture of $10$ mass $\%$ ethylene glycol is (in $^{\circ} C$)

What is molal depression constant? Derive an equation.