Hmm this is a good question, one I might have glossed over and missed lol. But looking at it initially I would say there is two ways to approach this problem.
1) With the allylic carbon, you assume any electrons are spread out over C2 and C3 due to resonance (including the electron).
2) try drawing out resonance structures. Two can be drawn for the allylic radical, but with the CC you just have the one.
Hope this helps