The correct answer is actually C. or the explanation of natural phenonmena. Most mythology-based belief systems, (a belief being a belief in and of itself doesn't make it a dogmatic belief of a cult or strict religion) are just a collaboration of beliefs. They are just beliefs of the explanation of natural phenonmena, nothing more, nothing less. Religions, which are often founded by cults, on the other hand, are all of that, plus what a person must and must not do in order to be worthy of something, usually being paradise in an afterlife. So, therefore, again the answer would be C.
I hope this helps. :)