The statement that best describes what it means for a hypothesis to have explanatory power is:
The hypothesis has been tested many times and over a wide variety of conditions.
A hypothesis with strong explanatory power can account for a variety of observations and empirical data, providing a framework for understanding phenomena and predicting outcomes in diverse situations. While testability is also an essential feature of a good hypothesis, the key aspect of explanatory power is its ability to effectively explain and integrate findings across different contexts.