Use the information on the graph to answer the question that follows.

POPULATION LIVING IN URBAN AREAS

IN CENTRAL AMERICA

Which of the following was the most significant cause of the population trend shown on the graph?

The depopulation of urban areas during periods of civil unrest and violence

The declining role of the peasantry in Central American economies

The establishment of effective urban renewal programs by Central American governments

The large$-$scale immigration to Central America from other areas of the world