Who did the caliph rule over?

The caliph, as the political and religious leader in Islamic governance, ruled over the Ummah, which is the collective community of Muslims, and dhimmi, referring to non-Muslim subjects who were granted protection and certain rights within an Islamic state. This reflects the foundational concept within Islam that emphasizes community and unity among its followers, highlighting the caliph's role as a protector and leader of both Muslims and permitted non-Muslims living under Islamic governance.

The term "Ummah" signifies a greater community that transcends individual tribes, clans, or areas, advocating for a unified society under Islamic law. The inclusion of dhimmi indicates the caliph's responsibility towards maintaining a balanced and just governance that respects the rights of those not adhering to Islam while integrating them into the societal framework.

In contrast, the other options, while they may involve authority and leadership roles (such as scholars, tribal leaders, or military generals), do not encapsulate the broader societal governance role that the caliph held over both Muslims and non-Muslims within the Islamic community.