Answer:
A. Islam.
Explanation:
The vast majority of Traders that focus their operation on Mediterranean coast of Africa and trans-Saharan caravan trade came from the middle east.
When business transaction occurred between these traders and African people, they socialize with one another. Over time, this created a cultural diffusion between them. The threaders share a lot of their cultures to the African people, including their religion. This was the reason why this trade Help to popularize Muslim in this region.
