Explanation

'Operation Flood', launched in 1970 by the National Dairy Development Board under Verghese Kurien, is popularly known as the White Revolution. It transformed India from a milk-deficient nation into the world's largest milk producer through a national milk grid linking producers to consumers. The Green Revolution (option A) refers to the increase in foodgrain production, the Blue Revolution (option C) to fisheries, and the Yellow Revolution (option D) to oilseeds. Hence option B.