According to this chart, how was Great Britain benefiting from its African colonies?

The exploitation of natural and ore resources and the slave trade.

Explanation:

The British had several colonies in the territory of Africa, and some of the most significant settlements are Gambia, Sierra Leone, Ghana. The British appropriated all the economy of the colonized areas. They used the natural and mineral resources of the conquered countries. Indigenous people worked for them, sending raw materials to Europe and Africa because there was more to the price. In the nineteenth century, the slave trade intensified so that a large number of the African population were victims of the slave trade. Large quantities of gold have been exploited from Africa to their home country, which is one of the most valuable resources the British have exported from Africa.

doesn't make any since

explanation:

the answer is a, salt plain