The correct answer is C. Trans-Saharan trade route
Step-by-step explanation
Trans-Saharan trade routes are a complex of roads that have allowed trade from the North African coast to the Sub-Saharan region (West Africa) since ancient times. Great empires developed in this region, including the Ghana Empire (750-1068), the Mali Empire (1235-1645), the Great Fulo Empire (1490-1537), the Songhai Empire (1350-1549), the Empire Wolof (1350-1549), among others. Therefore, the correct answer is the C. Trans-Saharan trade route.