Final answer:
The explanation that posits a mechanism for occurrences in the natural world and is confirmed through experiments and observations is a scientific theory, thus the correct answer is B. Theory.
Step-by-step explanation:
An explanation (which posits a mechanism) for the occurrences of some aspect of the natural world, based on knowledge that has been repeatedly confirmed through observation and experimentation, can be characterized as a scientific theory. The correct option is B. Theory. A hypothesis is a tentative explanation that begins the scientific process and upon rigorous testing and validation, it can develop into a theory. A law, in contrast, is a description of an observed phenomenon in the natural world that is concise and typically expressed mathematically. Theories are broader than laws and offer explanatory frameworks for understanding why natural phenomena occur as they do.