Which of the following contributed the most to increasing wealth and power of kingdoms in west, east, central, and south africa?
a. the ability to harvest salt as a resource and use it to increase trade networks.
b. the defeat of the arabs and the founding of the african sultanate.
c. the establishment of the solomonic dynasty in eastern africa and its rapid spread to the other kingdoms.
d. the positive alliance of these african nations with imperial europe.