The solution from the following with highest depression in freezing...

Depression in freezing point or elevation in melting point depends upon the number of solute particles rather than the kind of solute particles. 

Depression in freezing point (${\Delta T}_{f}$) is directly proportional to number of solute particles.

Also, ${\Delta T}_{f}$ is directly proportional to molality.

${\Delta T}_{f} = m \times {k}_{f}$

Amongst the given options acetic acid has lowest molecular mass.

The molar mass of acetic acid is $60 . 05$ g mol^-1.

Hence if the molecular mass is less, molality will be more, so the lowest freezing point will be shown by $180$gm of acetic acid in $1$L aqueous solution.