Answer:
B. They each facilitated the gold-slate trade
Explanation:
The importance of the sub-saharan african trades route and the saharan africa trade routes was that the north african caravans brought bars of salt from the north and trade them for gold, ivory, slaves and other items, but the main item that the north africans brought were the bars of salt since that was the main thing they could harvest from the desert, and by trading with the sub saharan african trade they managed to get other items needed like gold, slaves, skins, ivory, nuts, pepper, and other spices