The correct answer is D. Nigeria.
Step-by-step explanation
Nigeria is an African country located in the area of the Gulf of Africa (west of the continent), its capital city is Abuja, it is the most populous country on the continent. Regarding its climate it is warm. Due to its latitudinal location, its main economic activities are mining, gas and oil extraction. It is characterized by having a great cultural wealth because its population is native to different indigenous communities. According to the map presented, Nigeria is the country since it is located in the area of the Gulf of Africa that is the area circled in red. So, the correct answer is D. Nigeria.