Final answer:
The correct answer to the student's question is B. Theory. A scientific theory is a mature and well-substantiated explanation of natural phenomena that is supported by a vast body of evidence and has undergone rigorous testing.
Step-by-step explanation:
A scientific theory is a comprehensive explanation for a set of observations or phenomena that has been repeatedly tested and supported by evidence, often incorporating multiple hypotheses that have been validated by various experiments. This contrasts with a singular hypothesis, which is a tentative explanation that can be tested and refined through experimentation and observation—in essence, a foundation upon which a theory may be built once it has withstood extensive testing and gained considerable support from the scientific community.
In this context, the correct answer to the student's question is B. Theory. A scientific theory represents the pinnacle of scientific understanding after rigorous testing and validation, exceeding the initial scope of a hypothesis and providing a solid framework for understanding a natural event.