Final answer:
The Mongol Empire fractured into the Great Yuan, the Golden Horde, the Ilkhanate, and the Chagatai Khanate after the death of its leader, marking the end of a large unified political entity.
Step-by-step explanation:
The empire that fractured and split into the Great Yuan, the Golden Horde, the Ilkhanate, and the Chagatai Khanate after the death of its leader was the Mongol Empire. The Mongol Empire fractured into the Great Yuan, the Golden Horde, the Ilkhanate, and the Chagatai Khanate after the death of its leader, marking the end of a large unified political entity.
Upon the death of Kublai Khan, the Mongol world was already deeply fragmented due to infighting among Genghis Khan's descendants as well as substantial cultural and geopolitical changes, including religious conversions to Islam by the leaders of three out of the four khanates.
Despite attempts to maintain cohesion, the empire steadily declined, culminating in the loss of China in 1368, after which the Mongol Empire ceased to function as a unified political entity. Thus, the correct option is c) The Mongol Empire.