This question is incomplete. Here's the complete question.
Which of the following factors helps explain the rise of urban centers and the increase in trade in Afro-Eurasia during the second half of the thirteenth century?
A
The increase in all forms of coerced labor to build housing
B
The decline of the Mongol khanates across Asia
C
The reopening of Indian Ocean trade networks by Chinese explorers
D
The availability of safe and reliable transport along land-based trade routes
Answer: D The availability of safe and reliable transport along land-based trade routes
Explanation:
During the thirteenth and fourteenth centuries, Afro-Eurasia, which covered what are now Africa, Europe, and Asia, developed a trading system through land and water routes, known as the Silk Road.
Concentrated on urban centers, it connected eight geographical regions: the Persian Gulf, Central Asia's Northern Passage, the China Sea, Southeast Asia, the Arabian Sea, North Africa, the Eastern Mediterranean, and Western Europe.
