Out of benzene,$m$-dinitrobenzene and toluene,which will undergo nitration most easily and why?

(N/A) The ease of nitration depends on the electron density of the aromatic ring. Nitration is an electrophilic aromatic substitution reaction where the electrophile,nitronium ion $(NO_2^+)$,attacks the electron-rich ring.
$1$. The $CH_3$ group in toluene is an electron-donating group ($+I$ effect and hyperconjugation),which increases the electron density of the benzene ring,making it more reactive towards electrophilic substitution than benzene.
$2$. The $NO_2$ group in $m$-dinitrobenzene is a strong electron-withdrawing group ($-I$ and $-M$ effects),which significantly decreases the electron density of the benzene ring,making it the least reactive.
$3$. Benzene has intermediate reactivity.
Therefore,toluene undergoes nitration most easily. The increasing order of reactivity towards nitration is: $m$-dinitrobenzene < benzene < toluene.