Answer:
A; it has stood up to scientific inquiry and is considered the most robust explanation to date.
Step-by-step explanation:
A scientific theory is a generally accepted explanation for a way something works or functions. Unlike Laws, theories are not proven completely, however, they are highly backed by numerous studies, observations, etc. With time and the development of new technologies, theories have been changed numerous times throughout the past many decades. That said, current theories are the most up-to-date explanations we have for how the universe functions.
Therefore, A is correct.