The statement that best completes the timeline is:
B. The Ming dynasty expands China's Great Wall.
Explanation:
1. The timeline starts with people settling along the Huang He and Chiang Jiang rivers, indicating the early civilizations in China.
2. The Mongol Empire establishes the Yuan dynasty in China, which was a period of Mongol rule in the country.
3. Following the Mongol rule, the Ming dynasty comes into power, known for its significant expansion of the Great Wall of China.
4. Finally, the timeline ends with the People's Republic of China, marking the establishment of modern China.
Therefore, option B, which highlights the Ming dynasty's expansion of the Great Wall, fits best in completing the timeline of Chinese history.