Ghana, Kush, Songhai, Great Zimbabwe, Benin, and Kongo.
Explanation:
Ghana was in an ideal position to become a trading centre. The Ghana Empire became flourish and stronger in West Africa. Ghana Empire became prosperous because of salt and gold smelting. The Songhai grew in strength in the 1400s along the Niger River. Great Zimbabwe was known as a wealthy trading empire from the 11th century. The Benin kingdom began when the Edo people resided in the rainforests of West Africa in 900s. Kongo was the kingdom in west-central Africa which located in the south of the Congo River.
The economies of these kingdoms based on control of trade routes, food warehouses, and goods from the centre of Africa.
At the time, North and South Korea were just known as Korea, so it's neither of those two. I'd probably guess Hungary since it's closer to Germany than Greece is, but I'm not 100% sure.
