Final answer:
The World System Theory Stage is a concept in AP Human Geography that explains global social and economic inequalities and the interconnectedness of countries and regions.
Step-by-step explanation:
The correct answer is a) World System Theory Stage. The World System Theory is a perspective in sociology and geography that explains the emergence and development of social and economic inequalities on a global scale. It suggests that countries and regions are interconnected through economic, political, and social networks, and that these connections shape the development and wealth of nations. This theory proposes that world history can be divided into different stages, with each stage characterized by different levels of economic development and power distribution among countries.