C. petroleum.
There is a whole wikipedia page dedicated to the petroleum industry of Azerbaijan.
During the earlier times or era, it is known that many countries were under the power or authority of another through the colonialism. This was led by the European countries. When the colonial power is demolished, the country would be able to stand on its own, have its own leaders, lead its own government and people. Trading would also be improved not only intraterritorial but also interterritorial.
The forest with the dinosaurs
Although inequality was reasonably common in both the North and the South, it was more significant in the South. The Northern population was more likely to be middle class, as well as more likely to engage in different trades besides agriculture. This meant that education in the North was more common and widespread than in the South, where it was the privilege of a few lucky ones.