a$)$ Nitration of toluene shown in the chemical reaction below is an example of aromatic

substitution in which $o-$nitrotoluene and $p-$nitrotoluene isomers are the major products

making $97\%$ while $m-$nitrotoluene is only $3\%.$

Toluene

$o-$Nitrotoluene

$m-$Nitrotoluene

$p-$Nitrotoluene

$(63\%)$

$(3\%)$

$(34\%)$

Describe a stepwise mechanism using resonance to show the electron delocalization

in $o-,p-,m-$ carbocation intermediates of this reaction.