I think maybe the answer would be C. religious level of a ruling dynasty let me know if im wrong.
America’s next great conveyor belt of progress is the Erie Canal. When the Mississippi is opened up for trade, the Erie Canal became America's next great conveyor belt of progress. It is compared to the steamboats that spawn cities along its way. It gently converts New York into a prosperous town in which resulted for the town to quadruples its size.
Answer:
Large areas of Europe were conquered by Muslims. When these areas such as southern Spain were recaptured and placed under Christian rule Muslim customs and architecture remained. Christians were encouraged to go on Crusade to recapture Jerusalem from the Muslims.