JEE Main 2023 Chemistry question

20% of acetic acid is dissociated when its when 5 g is added to 500 mL of water. The depression in freezing point of such water °C. Atomic mass of C, H and O are 12, 1 and16 a.m.u. respectively. [Given : Molal depression constant and density of water are 1.86 K Kg and 1 g respectively.]