(s) about acidity and basicity.

(A) Correct. The $p$-nitro group stabilises the phenoxide by $-R$ and $-I$ effects ($pK_a\approx7.2$), phenol has $pK_a\approx10.0$, and the electron-donating methyl group in $p$-cresol (hyperconjugation, $+I$) destabilises the anion ($pK_a\approx10.3$). (B) Incorrect. In water, the steric hindrance to solvation of the ammonium ion makes $(\mathrm{CH_3})_3\mathrm{N}$ ($pK_b\approx4.2$) weaker than $\mathrm{CH_3NH_2}$ ($pK_b\approx3.4$). (C) Correct. In the ortho isomer the nitro group exerts the strongest $-I$ effect and the ortho effect, giving $pK_a\approx2.2$, versus about $3.4$ for the para isomer and $4.2$ for benzoic acid. (D) Incorrect. Fluorine is more electronegative and exerts a stronger $-I$ effect than chlorine on the carboxylate, so $\mathrm{FCH_2COOH}$ ($pK_a\approx2.6$) is stronger than $\mathrm{ClCH_2COOH}$ ($\approx2.9$).