The correct answer is B) importation of porcelain from China.
The Abbasid Caliphate benefitted MOST from the importation of porcelain from China in the latter centuries of the First Millennium.
In the history of Muslim dynasties, the Abbasid Caliphate was one of the most important and representatives. The caliph was the name of the ruler of the empire. The first period of this caliphate started in 750 and ended in 1258 CE when the Mongols invaded the capital city Baghdad. The reign moved to Cairo, Egypt during the second period from 1261 to 1517 CE. During the later centuries of the First Millennium, The Abbasid Caliphate benefitted most from the importation of porcelain from China.