A good scientific theory:
a. is arrived at by chance.
c. is not provable.
b. is the foundation of the scientific method.
d. accurately predicts the results of future experiments.
I would have to say none of the above. B is probably the correct answer, but even this does not truly make sense as an answer. At least that is not what I would say at first. A scientific theory is an explanation for phenomenon in the universe.