Employment opportunities were limited in Tijuana. Manuel, who had been unemployed for several months, decided to join a group of people traveling north to find work.

What concept is described by the paragraph above?

a)population growth

b)urbanization

c)push-pull

d)sustainable development

See comment below in response to this question.

The concept described in the paragraph above is option c) push-pull.

Explanation:
The paragraph talks about Manuel, who decides to join a group of people traveling north to find work because employment opportunities were limited in Tijuana. This situation illustrates the push-pull concept in migration studies. Push factors refer to the circumstances or conditions that push individuals or groups to leave their place of origin, such as limited employment opportunities. Pull factors, on the other hand, refer to the circumstances or conditions that attract individuals or groups to move to a particular destination, such as the prospect of finding work in a different location. In this case, the limited employment opportunities in Tijuana are the push factor, while the possibility of finding work elsewhere is the pull factor. Hence, the concept described in the paragraph is push-pull.