As observed in the school laboratory, acetic acid is

Acetic acid ($CH_3COOH$), listed in Table 4.1, is a clear, colourless liquid at room temperature. It has a very distinct, sharp, and pungent smell characteristic of vinegar, as vinegar is essentially a dilute solution of acetic acid. Option A is incorrect because it is not blue and does not have a fruity smell (esters have fruity smells). Option C is incorrect because it has a very strong, recognizable odour. Option D is incorrect because the 'rotten egg' smell is characteristic of hydrogen sulphide ($H_2S$), not acetic acid.