Which of the following is a resonance contributor of the radical shown below?

Step-by-step solution

The given structure is an allylic radical. Let the top carbon with the unpaired electron be C1. Moving clockwise, the methyl group is attached to C2 and the double bond is present between C2 and C3. The unpaired electron on C1 is in conjugation with the C2=C3 bond. Delocalization occurs such that the double bond shifts to C1=C2 and the unpaired electron moves to C3. The resulting resonance contributor must have the radical on the bottom-right carbon (C3). is the only structure that correctly shows the unpaired elec