I actually have a question about this problem too.
In the explanation you mention that if the diene is funky looking like it is in the problem, then if both of the bonds have same chemistry, ie are Z, Z; or E, E; then the substituents in the product will end up cis in the product. So, why wouldn't 2 work? Number two is a diene that is E, E, and number 3 is Z, Z. Why can't number two adopt a cisoid formation?