Answer: D. scientific law
Step-by-step explanation:
A scientific law is a statement which is based upon the natural process, phenomena or event which is based upon repeated trials of experiments. But it does not explanation for the cause of natural process or phenomena or event. The scientific law is abide by all the scientific communities and it cannot be changed or manipulated.
The conservation of energy is a scientific law. As it cannot be changed and it is demonstrated without including any exception under any condition.