Which of the Following Statements About Scientific Theories Is Not

Which of the following statements about scientific theories is not true?

A) A theory must make predictions that can be checked by observation or experiment.
B) A theory is a model designed to explain a number of observed facts.
C) A theory can never be proved beyond all doubt; we can only hope to collect more and more evidence that might support it.
D) If even a single new fact is discovered that contradicts what we expect according to a particular theory, then the theory must be revised or discarded.
E) A theory cannot be taken seriously by scientists if it contradicts other theories developed by scientists over the past several hundred years.