This is another question that we usually cover in class during our analyze the argument structure lesson. First step is to pin down the argument:
People have positive and negative reactions to nonsense words ----> People respond to the sound of a word, not just to its meaning
Fairly straightforward argument. The part they ask about is a premise so (B) and (E) aren't even in the running.
(D) gives us a succinct statement of the argument. We already know it's a premise but this one has the right conclusion. It's a winner.
The wrong answers are fairly typical here:
(A) is good from afar but far from good. The conclusion is that people react to the way words sound. That does not mean they have a reaction to every word. In fact, people are probably neutral on most words.
(B) is the wrong role. It's not a conclusion. Move on.
(C) is in trouble right from the start. I've never seen a role question with the right answer of a "generalization." But the premise they are asking about isn't general at all; it's based on the results of a specific study.
(E) is the wrong role again. It's not a conclusion. Don't waste time reading the rest of this.
I hope this helps. If you still have a question after reading this, post away!
Demetri