(A) In m - nitrochlorobenzene and p - Nitro chloro benzene, m - chloronitrobenzene is more reactive towards aqueous KOH.
(R) Carbanion is more stable in m - Nitro chloro benzene

Reaction of nitro chlorobenzene with aq.KOH is aryl nucleophilic substitution reaction.More the magnitude of positive charge on benzene ring faster is nuclophilic substitution reaction. Presence of electron withdrawing groups increases positve charge on benzene ring and facilitates the reaction.During this reaction intermediate formed is carbanion, stabilised by resonance when EWG are present at o and p positions. EWG group present at meta position is stabilised by inductive effect only.