B. Liberal economic policies opened the region to trade.
Explanation:
The Green Revolution is the name used internationally to describe the important increase in agricultural productivity and therefore food between 1960 and 1980 in the United States and later extended by many countries. It consisted in the planting of varieties of wheat, corn and rice, mainly, more resistant to extreme climates and pests, capable of achieving high yields through the use of fertilizers, pesticides and irrigation.
