The three religions that were significant along the Indian Ocean trade route, particularly in relation to the regions you mentioned, would primarily include:
- Islam - Spread widely through trade across East Africa and the Middle East, and influencing trade relations with India.
- Hinduism - Particularly present in India, influencing trade connections with Southeast Asia and the broader Indian Ocean region.
- Buddhism - Historically significant in parts of East Africa and Southeast Asia, though less common in direct trade partners along the Indian Ocean.
Among the options provided, East Africa, Mediterranean, and India seems to capture major regions involved in the Indian Ocean trade where these religions played a role. Each of these areas had traders and communities that were influenced by and practiced different religions which were interconnected through the trade routes.