Correct decreasing order of acidic strength is

EWG increases the acidic strength of phenol , nitrophenols are more acidic than phenol-NO2 grp . . . o, p  . . .   -I, -M  . .  . .  strong EWG-NO2 grp . . . meta  . . .   -I, only  . . .  weak EWG∴ ortho and para nitrophenols are more acidic than meta nitrophenol.In ortho nitrophenol due to chelation, proton is less available for donation.Acidic strenngth of C > D > B > Apka of C(7.1) < D(7.2) < B(8.3) < A