Given are cyclohexanol (I), acetic acid (II), 2, 4, 6 - trinitrophenol (III) and phenol (IV). In these, the order of decreasing acidic character will be

The correct option is B. III > II > IV > I

Due to the strong -I and -R effect of the three-NO₂ groups present in 2, 4, 6 - trinitrophenol (III) makes it more acidic than CH₃COOH (II),
further, due to greater resonance stabilization of acetate ion over Phenoxide ion, acetic acid (II) is a stronger acid than phenol (IV).
Since alcohols are less acidic than phenols, therefore, cyclohexanol (I) is less acidic than phenol (IV).

Thus, the overall acidic character decreases in the order 2, 4, 6 trinitrophenol (III) > acetic acid (II) > phenol (IV) cyclohexanol (I). i.e. option (b) is correct.