The answer here would be D.
In science the term theory is a bit different than the everyday use of the word theory. In science theory is not a hunch and or an idea that came out of nowhere but an interpretation of the facts that is a product of much rational examination. Theories can change but the facts themselves will not. A trait of a good theory can be its predictability that is that the things will happen how the theory will say it will happen so the theory should be testable.