The counts and barons of Flanders were vassals of the king of

A. Spain

B. England

C. Portugal

D. France.

The counts and barons of Flanders were vassals of the King of France. The answer to this item is letter D. These titles were used during the 1789 wherein the royalty can be obtained or achieved through; (1) birth, (2) position in an office, and lastly through the grant from the authority given with the letters.

The counts and barons of Flanders were vassals of the king of France, and the French tried to regain control of Flanders in order to control its wealth.