Q.Which of the following reagent can be used to convert nitrobenzene to aniline ?

Nitrobenzene's own chemistry extends the general nitro-reduction ladder and adds ring-specific electrophilic substitution. REDUCTION STAGES (agent/medium sets the stopping point): Sn/HCl (acid, 6[H]) gives aniline; Zn/NH4Cl (neutral, 4[H]) gives phenylhydroxylamine; Fe/H2O steam (2[H]) gives nitrosobenzene; ALKALINE conditions (Zn/NaOH) instead trigger self-condensation of the partially-reduced intermediates to azobenzene, reducible further (2[H]) to hydrazobenzene. ELECTROLYTIC REDUCTION forks by acidity: weakly acidic gives aniline directly; strongly acidic traps phenylhydroxylamine, which rearranges (acid-catalysed) to p-aminophenol. CATALYTIC/HYDRIDE REDUCTION (Ni or Pt/H2, or LiAlH4) gives aniline + 2H2O. SELECTIVE REDUCTION of a POLYnitro ring: (NH4)2S reduces only ONE -NO2 of m-dinitrobenzene, giving m-nitroaniline (the other -NO2 survives untouched). ELECTROPHILIC SUBSTITUTION: -NO2 is strongly deactivating and meta-directing, so …