Which one of the following, if substituted for the constraint that no two consecutive commercials can be long, would ...

Could someone please explain to me why Answer Choice "E" here is correct? I picked Answer Choice B. The hypothetical drawn out for both Answer Choice B and Answer Choice E is as follows: Commercial: I H K F G Version: S S L S L I thought this was the correct choice because there would be two repeating S versions. I thought Answer Choice "E" did the same thing. It states the second and fourth commercial must be short. Commercial: G F I H K Version: L S L S L How is this the right answer choice and "B" is not? Any help would be greatly appreciated!