Chemistry - GOC Question with Solution | TestHub

In A, the negative charge and pi bonds move within the same cyclohexadienyl-anion framework. In $\mathrm{C}$, the allylic positive charge and its adjacent pi bond move without changing any atom position or sigma bond. $\mathrm{B}$ places oxygen on different carbon atoms; $\mathrm{D}$ changes a ring into an open chain. These are not resonance changes. Therefore A and $\mathrm{C}$ are correct.