Chemistry - GOC Question with Solution | TestHub

$\mathrm{I}$ – Cross conjugation or relativity less benzenoid form in all resonance structures (Fries rule)

$\mathrm{II}$ – Extended conjugation or more benzenoid form in all resonance strutures (Fries rule)

$\mathrm{III}$ – 4 $\alpha$ hydrogens

IV – 3 $\alpha$ hydrogens