Final answer:
Temujin, after being elected Genghis Khan in 1206, focused on expanding his power and forming the Mongol Empire, which became one of the largest empires in history.
Step-by-step explanation:
After being elected Genghis Khan by the Mongols in 1206, Temujin devoted himself to conquest and ultimately succeeded in founding the Mongol Empire. The direct answer to the question is option (d): Devoted himself to conquest, eventually creating the Mongol Empire. He was a skilled raider and as he won more raids, his followers grew in number substantially. Those who were loyal to him were treated like family, while he showed no mercy to his betrayers. Uniting many tribes under his rule, he formed a significant confederation, leading to the establishment of a vast empire that would later include several major regions including China and parts of the Islamic world.
Genghis Khan was not assassinated by the previous Khan, nor did he convert to Islam or make an alliance with the Tang dynasty, as the other options suggest. His descendants, such as Kublai Khan, continued his legacy and expanded the empire even further. The Mongol Empire under Genghis Khan became one of the largest contiguous empires in history, drastically changing the course of world events.