The correct answer is - South Africa.
Cecil Rhodes was a colonialist that managed to create huge fortunes by controlling the diamond exports in the southern part of the African continent. His influence and control were predominantly in what are now the countries of Zimbabwe and the Republic of South Africa, with Zimbabwe being initially named after him, Rhodesia.
The people in this region didn't had a clue that the diamonds are something very valuable on the global market and that they can earn fortunes from them, and Rhodes used that in his advantage. The local people were employed in the excavation of the diamonds, and were payed little to nothing, while Rhodes was making huge wealth on their back.