Answer: D. Charlemagne
Explanation: Charlemagne, also known as Charles the Great, Charles I, was the king of Franks in 768. Charlemagne also known as Charles the Great, Charles I, was the king of Franco in 768. He became the Roman Emperor of the AC 800, which is a large part of Western and Central Europe, in the so-called Early Middle Ages and is considered the successor of the Western Roman Empire. The first significant ruler of Western Europe after the fall of the Western Roman Empire.