Calculate the freezing point of an aqueous solution of a non-electrolyte having an osmotic pressure 2.0atm at 300K.$K_f=1.86Kmol^{-1}kg$ and $S=0.0821$litre atm $K^{-1}mol^{-1}$

Question

$\begin{array}{1 1}-0.151^{\large\circ}C\\-0.251^{\large\circ}C\\-0.351^{\large\circ}C\\-0.101^{\large\circ}C\end{array} $