Final answer:
Flanders was the center of trade in northern Europe during the 15th century, known for its prosperous cities and cultural patronage. The correct option is A.
Step-by-step explanation:
The center of trade in northern Europe during the fifteenth century was located in Flanders. During this time, Flanders was under the control of the Dukes of Burgundy and was known for its prosperous industrial and banking cities that supported a large middle-class population.
Rich with artistic patronage from the court of the Dukes of Burgundy as well as from wealthy private citizens, Flanders became a hub of cultural and economic activity, making it a significant center for trade and commerce.