The correct answer is A because the principal effect of the Green Revolution was an increase of chemical pesticides and fertilizers. They were extremely important to agriculture, and Thanks to the use of these new substances like fertilizers, synthetic herbicides and pesticides, farmers were now able to have better control over the plagues that normally minimized the production of crops.
At the same time, the implementation of multiple cropping techniques in conjunction with the use of chemical pesticides and fertilizer, allow the agricultural industry to have high-yields crops, and significantly increment the production of food in the country.