Ascientific theory is

a. a hypothesis that has been rigorously tested and never been disproven.
b. a hypothesis that has been rigorously tested and only been disproven a few times.
c. an opinion.
d. a hypothesis that has been tested at least five times.
e. an idea based on a person's experience or knowledge.

The correct answer is A. a hypothesis that has been rigorously tested and never been disproven.

Explanation:

A hypothesis is an idea or guess or a proposed explanation of any phenomena. When the hypothesis is checked and proved by many experiments and cannot be disproven by anyone then it considered as a scientific theory.

Therefore a scientific theory is a hypothesis that has been rigorously tested by the performing different experiments and never been disproven. For example theory of evolution, natural selection which tell us about the evolution of organism on earth which is proven by Darwin. So the right answer is A.