How Did Expanding Agricultural Production in Places Like Argentina and the American

How did expanding agricultural production in places like Argentina and the American West lead to the migration of rural populations to cities?

A) Increasing output in the countryside created a new prosperity that allowed rural populations to travel.
B) Since the growing agricultural output attracted ever-larger numbers of immigrants to the countryside, the older generations of rural settlers left for the cities.
C) Increasing output worldwide pushed down the prices of farm products, making it more difficult for farmers to make ends meet.
D) New production methods that were at the heart of growing farm productivity alienated many rural folks familiar with traditional farming practices.