The right option is; push-pull
Push pull is the concept described by the paragraph above
Push-pull is used to describe why individuals move from one location to another. Push-pull occurs due to the push factors, and pull factors which may be economic, social, political or environmental in nature. The push factors are the conditions such as unemployment, and famine that drive people away from an area while the pull factors are the conditions such as employment, and political freedom that attract people to move to a certain area.