Which religion spread most prominently thanks to trade routes on the Indian Ocean?

Islam often followed existing trade networks, and Muslim communities can be found not just along the Swahili coast in East Africa, but also in Indian and Chinese port cities as early as the 8th century. Eventually, Islam became a robust presence throughout the Indian Ocean world's trading networks and port cities.

it would have to be gasioline

the allies' desire to seek retribution for germany's actions