The correct order of the following compounds showing increasing tendency towards nucleophilic substitution reaction is :-

For nucleophile substitution in aromatic halides

Correct order is :

(i) $<$ (ii) $<$ (iii) $<$ (iv)

More $\mathrm{No}$. of $\mathrm{NO}_{2}$ substituted aromatic halide, increase the rate of nucleophile substitution reaction in aromatic halides.