The statement that provides the BEST explanation of why the Roman Empire came to an end is:
The vastness and diversity of the geography, culture, and people who came under Roman rule posed increasingly difficult challenges for governance.
This statement highlights the complexities and difficulties associated with managing a large and diverse empire, which is recognized as a significant factor in the decline of the Roman Empire. The challenges of governing such a vast territory that included diverse cultures and languages made effective administration increasingly difficult, leading to instability and fragmentation.