The combination between religious and political aspects in the Abbasid state's concept of rulership is best reflected in which of the following?

A. The Abbasid state had an influential Sunni religious class that often came into conflict with the state.

B. The Abbasid state often allowed local rulers considerable autonomy.

C. The Abbasid state patronized the construction of religious buildings such as mosques.

D. The Abbasid state was headed by a caliph who was theoretically the state's supreme religious and political leader. ​