The freezing point of a solution containing 0.2g of acetic acid is 20.0g of benzene is lowered by $0.45^{\large\circ}$C. Calculate the molar mass of acetic acid from this data?[For benzene,$K_f=5.12Kkg mol^{-1}]$

Question

$\begin{array}{1 1}113.77g mol^{-1}\\170g mol^{-1}\\180g mol^{-1}\\190g mol^{-1}\end{array}$