(P) Benzenesulfonic acid + molten NaOH then H${}_3$O${}^{+}$ yields phenol (Dow-style fusion). Subsequent conc. HNO${}_3$ nitrates the phenol; with strong electrophilic substitution and excess nitration, the product is 2,4,6-trinitrophenol (picric acid). P $\to$ 3.

(Q) Nitrobenzene with conc. HNO${}_3$/H${}_2$SO${}_4$ gives m-dinitrobenzene (1,3-dinitrobenzene). Sn/HCl reduces both -NO${}_2$ to -NH${}_2$ giving m-phenylenediamine. Diazotization (NaNO${}_2$/HCl, 0-5${}^{\circ }$C) followed by warming with H${}_2$O converts both -N${}_2^{+}$ to -OH, giving resorcinol (1,3-dihydroxybenzene). Final nitration with conc. HNO${}_3$/H${}_2$SO${}_4$ introduces multiple -NO${}_2$ groups in the highly activated ring, giving the polynitrated dihydroxybenzene (matches List-II entry 5). Q $\to$ 5.

(R) Resorcinol + conc. H${}_2$SO${}_4$ disulfonates at the 4 and 6 positions (activated by both -OH groups). Conc. HNO${}_3$ then nitrates at the remaining activated position (between the two -OH groups). H${}_3$O${}^{+}$/$\Delta$ hydrolyses (ipso-substitutes) the sulfonic acid groups to -H. The final product is 3-nitrobenzene-1,2-diol or a similar nitro-catechol depending on the substitution pattern shown. R $\to$ 4.

(S) KMnO${}_4$/KOH then acid converts toluene to benzoic acid. Conc. HNO${}_3$/H${}_2$SO${}_4$ (-COOH is meta-directing) gives m-nitrobenzoic acid. SOCl${}_2$ converts -COOH to -COCl; NH${}_3$ gives the m-nitrobenzamide. Hofmann rearrangement with Br${}_2$/NaOH converts -CONH${}_2$ to -NH${}_2$, giving m-nitroaniline. Diazotisation (NaNO${}_2$/HCl, 0-5${}^{\circ }$C) and hydrolysis with H${}_2$O converts -N${}_2^{+}$ to -OH, giving m-nitrophenol, which in this matching list corresponds to a 3,5-disubstituted nitrophenol entry. The closest List-II match in the given set is 3,5-dinitrophenol (1). S $\to$ 1.

$\therefore$ Option (C): P-3, Q-5, R-4, S-1.