Answer:
We can say that this is the correct answer as in this period was on of the most important centers in the world.
Explanation:
Baghdad was the capital of Caliphate until 1258 and was regarded as one of the largest and most important cities in the world. It was a crossroad of trade and people from the whole world were coming here to trade. Of course, Abbasid Caliphate was of the largest countries of that period and stretched across two continents, which enabled Baghdad to be an important center.
