Final answer:
The coinciding golden ages of India, Spain, and West Africa are best explained by cultural diffusion and trade networks which facilitated the spread of ideas, goods, and technologies leading to a period of prosperity interconnected by global trade.
Step-by-step explanation:
The best explanation for the coinciding "golden ages" of India, Spain, and West Africa is likely C) Cultural diffusion and trade networks. These regions were extensively involved in trading networks that not only spread goods but also ideas, technologies, and cultural practices. In India, cultural diffusion was fueled by maritime trade, which was enhanced by the monsoons.
The Arab invasions and the Bantu migrations promoted cultural and commercial exchanges across Africa, leading to the unification under Islam and the development of trade in gold, salt, and slaves. Similarly, trade along the Sahara and the spread of Islam through North Africa established economic and cultural links with West Africa, further bolstering regional prosperity.
The trade in commodities such as gold, which was used to mint European coins, highlights the global impact of these networks. Additionally, the trade-based societies that developed along the Indian Ocean signify the interconnectivity of these regions.