The benzene ring shown is the parent of four substituted benzenes (structures A to D). Select the structures whose mono-nitration gives mainly the meta isomer.

The groups are $\mathrm{CF}{}_3$ (trifluoromethylbenzene), $\mathrm{CN}$ (benzonitrile), $\mathrm{Cl}$ (chlorobenzene) and $\mathrm{N}{}^{+}(\mathrm{CH}{}_3){}_3$ (trimethylanilinium). $\mathrm{CF}{}_3$, $\mathrm{CN}$ and $\mathrm{NMe}{}_3{}^{+}$ are strongly electron-withdrawing with no lone pair to donate, so they deactivate the ring and direct meta. Chlorine donates a lone pair by resonance and is therefore ortho/para-directing even though it deactivates.