On the map, which letter represents the country that was MOST affected by the Green revolution?

Answer:
Letter B - India/Pakistan
Explanation:
The venue of the Green Revolution in India allowed to prevent a massive famine in India and Pakistan in the early 1960's, saving a great number of people in this second most populated country of the world.
A Mexican research team introduced a new variety of wheat in India during that period and that earned them a Nobel Prize in 1970.