Match the four starting materials (P, Q, R, S) given in List I with the corresponding reaction schemes (1, 2, 3, 4) provided in List II and select the correct answer using the code given below the lists.
Column I — P: ethyne (HC≡CH); Q: benzene-1,3-diol (resorcinol); R: nitrobenzene; S: 4-nitrotoluene
Column Ii — 1: side-chain oxidation, acid-chloride formation and amidation scheme; 2: nitro-group reduction, amine protection, sulfonation, nitration, desulfonation and deprotection scheme; 3: ethyne cyclotrimerisation, nitration, selective reduction, diazotisation and hydrolysis scheme; 4: resorcinol sulfonation, nitration and desulfonation scheme