For the three potential-energy graphs shown (with total energy E marked), identify the forbidden regions where a particle cannot be found. The example graph is only illustrative.

Options

• Option A

  Graph 1: all x; Graph 2: x<a or x>b; Graph 3: -b/2<x<-a/2 and a/2<x<b/2

• Option B

  Graph 1: x>a only; Graph 2: a<x<b; Graph 3: |x|<a/2

• Option C

  Graph 1: none; Graph 2: x<a; Graph 3: |x|>b/2

• Option D

  Graph 1: all x; Graph 2: a<x<b; Graph 3: -a/2<x<a/2