How did the kingdom of benin differ from the kingdom of songhai during the postclassical era?
a. songhai's leaders converted to islam, while benin's leaders maintained their native religion.
b. benin grew wealthy through the gold-salt trade, while songhai grew wealthy through the silk trade.
c. benin grew wealthy through the coffee trade, while songhai grew wealthy through the silver trade.
d. songhai established a democratic form of government, while benin did not.