The correct answer is B. They facilitated cultural exchange and the movement of traders who shared religious beliefs.
Trade routes played a crucial role in the dissemination of Islam from the Arabian Peninsula to various regions, including Africa and southern Europe. These pathways allowed for the movement of merchants and travelers who not only engaged in commerce but also shared their cultural and religious beliefs. Through trade interactions, ideas and beliefs were exchanged, leading to the spread of Islam as traders and local populations interacted. This process often involved the establishment of relationships and communities that helped Islam to take root in diverse areas.