Which of the following statements is most accurate regarding trans-saharan trade?
a) while gold and slaves were often sold, lucrative salt was not introduced to africa until the portuguese arrived on the western shores.
b) for the most part, trade between west africans and arabs were peaceful and included the exchange of gold and slaves for weapons and horses.
c) trans-saharan trade completely stopped after coastal ports provided a new means for trade.
d) because of the tremendous size of the sahara desert, it served as a barrier, isolating africa from the rest of the world.