The best explanation of the relative significance of the trans-Saharan and Indian Ocean trade routes is:
The routes were equally significant—each in its own way—as they both contributed to significant cultural developments along the routes, and worth cannot be measured simply by the goods that were traded.
Both trade routes played vital roles in connecting different cultures, facilitating trade of diverse goods, and influencing social, economic, and political developments across regions. The Indian Ocean trade routes allowed for interactions between Africa, the Middle East, and Asia, while the trans-Saharan routes connected North Africa with sub-Saharan Africa, allowing for the exchange of valuable resources and cultural ideas.