While the passage does not explicitly say "scientific," we are dealing with theories of human behavior, and their predictive power. Psychology is science (albeit a "softer" science), so we are discussing scientific theories. I would try not to overly rely on using a single word to eliminate an answer choice on the grounds of scope. While sometimes one word makes an answer wrong, that would likely be an "all, always, never" type of word. While I agree "scientific" may feel a little strong, it would be hard to argue that the author could reasonably disagree with B.