Final answer:
West African leaders recognized the importance of northern African trade routes for spreading the religion of Islam and facilitating the trade of valuable resources, strengthening cultural and economic connections across the Islamic world.
Step-by-step explanation:
West African leaders knew that establishing trade routes in northern Africa was important primarily because it spread the religion of Islam and shared precious resources through merchant travelers. The trans-Saharan trade routes were crucial for moving goods like gold, ivory, and salt from West Africa to trading centers in North Africa and beyond. This trade brought about a significant spread of Islam, as Muslim traders and merchants used these routes, reinforcing and expanding their religious and cultural influence. The adoption of Islam by West African elites and merchants facilitated mutual trust and respect, which in turn promoted increased trade activity. Arabic, the language of commerce within the Islamic world, further unified these trading networks. Additionally, the trade was financially beneficial to states, as they profited from taxes levied on the transported goods.In conclusion, option A is the main answer. These networks did more than just trade; they also spread Islam throughout the regions connected by these routes. It wasn't merely about the exchange of goods but also the exchange of cultures, practices, and ideas, strengthening the relations between the different civilizations with the shared characteristic of following Islam.