Starting in the Middle Ages, swahili became the "lingua franca," or common language, in trading ports along the eastern coast of Africa. What conclusions can you draw about Africans and trade, based on this fact? Select one:
a. Swahili as a language was created for the purposes of trade.
b. The native Africans controlled the trade that took place in their ports.
c. Traders from other cultures controlled the trade that took place in African ports.
d. Swahili is a language that came from Persian or Arabia originally.