The correct option is B Both A and R are true, but R does not explain A.
The Green Revolution introduced disease-resistant crop varieties. Since the plants were immune to the infections, they lived longer, and their production increased.
However, different parts of India achieved different growth rates of foodgrains. States like Uttar Pradesh and Madhya Pradesh produced excess wheat while certain states lagged. The government introduced a stock and distribution system to overcome such regional disparities.