Order of **acidity** among these substituted phenols: phenol (P), p-nitrophenol (N), p-cresol (C, methyl substituent), p-methoxyphenol (M):

p-NO₂ is strong −M, −I — stabilises phenoxide (most acidic). p-CH₃ is +I (mildly destabilises phenoxide; weakly basic). p-OMe is +M (lone pair donates into ring) — strongly destabilises phenoxide (least acidic). So: p-NO₂ > unsubstituted > p-CH₃ > p-OMe.