How does the modern era differ from the Middle Ages?

A. States established manorialism as their major economic system during the modern era, while capitalism dominated the Middle Ages.
B. Imperialism plays a major role in the modern era, while countries were too weak to establish empires during the Middle Ages.
C. The exchange of goods and ideas among cultures is uncommon during the modern era, but it occurred frequently during the Middle Ages.
D. Technology allows people in the modern era to mass-produce goods more quickly and easily than was possible in the Middle Ages.