Final answer:
The Mongols chose Temujin to be Genghis Khan in 1206, meaning "strong ruler". This title marked him as the supreme leader of the Mongol Empire.
Step-by-step explanation:
In 1206, the Mongols chose Temujin to be Genghis Khan, which means "strong ruler". The correct answer to the question is C) Genghis Khan.
Temujin gained control of a formidable force on the Eurasian Steppe, eventually earning him the title of khagan, meaning 'khan of khans' or 'supreme ruler'. As Genghis Khan, he united the Mongolian tribes and established a legacy as the founder of the Mongol Empire. His role in history is critical, as he and his descendants, such as Kublai Khan, greatly impacted the geopolitical landscape of Eurasia.