"Studies indicate few Americans" - that does not make sense if we would keep that allone as it stands. Whenever I read something like this I feel like there has to be some contrast word in order for this sentence to be complete.
On top of that this is a subtle meaning issue imho. "Studies indicate few Americans" -> well studies no not indicate few americans, they indicate THAT few americas are willing to pay...
(A) and (C) are out for me.
(B) is out of the race because it has a very weird structure. "nor ..." without the neither is a no-no for me. Maybe there are some cases where this works out, but in this one it does sound totally awkward and we have much better answer choices anyway.
(D) "... americans are willing to pay a higher cost for fresh food and are not taking the time" - parallelism issue. "willing to pay <-> not taking the time" something is off here
(E) "... are willing to pay a higher cost for fresh food or to take the time" -> corrects the issue we saw in (D)