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 (ΔTf) is directly proportional to number of solute particles.
Also, ΔTf is directly proportional to molality.
ΔTf=m×kf
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 180gm of acetic acid in 1L aqueous solution.