Where did the abbasid dynasty establish their caliphate

The Abbasid dynasty established its caliphate in Baghdad, Iraq.

Explanation:

The Abbasid dynasty established its caliphate in Baghdad, Iraq. The caliphates remained in the region for about three centuries.  The Abbasids established caliphates in Baghdad for 3 centuries, the result of which was the strengthening of Islamic rule in the region. The caliphates influenced the local culture and science by providing technological advances for the time and the cultural richness of the region. The Abbasid caliphate began to lose power in Baghdad when non-Arab citizens began to gain power and influence in the region around 940 CE.

it would be d). more resources must be obtained to attain that combination of goods and services