The correct answer is - North Africa.
North Africa is the region in Africa that has its main economic activities based around the production of oil phosphates and natural gas. The reasons for this are that the region has solid amounts of reserves of oil and natural gas in its territory, but also because big portion of the other economic activities are restricted because of the geography of the region. This region is almost entirely covered by desert, with little pockets that have Mediterranean climate along the coast. That is not allowing for lot of economic activities to take place, so the oil and the natural gas are by far the most exploited and bring in the biggest income.