Which of the following is not part of a good scientific theory?
a. a scientific theory must explain a wide variety of phenomena observed in the natural world.
b. a scientific theory cannot be accepted until it has been proven true beyond all doubt.
c. a scientific theory must make testable predictions that, if found to be incorrect, could lead to its own modification or demise.
d. a scientific theory should be based on natural processes and should not invoke the supernatural or divine.