Which of the following rivers is not included in Africa's important economic history?

The Amazon River is not included in Africa's important economic history because it is located in South America, primarily flowing through Brazil and parts of Peru, Colombia, and several other countries on that continent. In contrast, the Nile, Congo, and Zambezi rivers are significant to Africa’s economic history due to their crucial roles in trade, agriculture, and cultural development across various regions of the continent. The Nile River, for example, has been central to the agricultural and economic practices of Egypt for thousands of years, while the Congo and Zambezi Rivers have similarly influenced trade and livelihoods in their respective areas. Therefore, the Amazon does not relate to Africa's historical economic frameworks, setting it apart from the other rivers listed.