The correct answer is B. human systems.
In geography, a human system is a set of interconnected elements that involve human societies, their interaction with the natural environment and how cultures, economies, technologies, among other human aspects shape the different regions of the Earth.
Migration is one important element of human systems. Human migration refers to the displacement of human populations, which produces economic, cultural, demographic, social, and political changes in both, the societies that send migrants and the societies that receive them, and also in the natural environment of these societies.
Interdependence is another relevant characteristic of human systems. It refers to the level of interaction between different aspects of human societies and the physical environment and how they mutually re-shape.
