The World Systems Theory suggests:

A) that what happens to cities in relation to urban population and economic growth is directly a result of where they fit in the world hierarchy of cities.
B) that the economic, social, political, and even arguably psychological conditions of a city are due to its relative position in a global hierarchy.
C) that what happens to individual cities is a direct result of the economic activity within their own city boundaries only.
D) that hierarchy is based upon how large the population is.