The presence of nitro group on benzene in nitrobenzene shows –I effect thereby deactivating the ring and also decreases the electron density at ortho and para positions as compared to meta position. This can be shown through the following resonating structures of nitrobenzene-

Therefore, option (i) and (iii) are correct. (i) Deactivates the ring by inductive effect. (iii) Decreases the charge density at ortho and para position of the ring relative to meta position by resonance.