Question: What is the invention of the social entrepreneur whose life is the subject of an upcoming 2018 Indian film called 'Padman' ?
Sentence (from "Verghese Kurien"): It made India the world's largest milk producer, surpassing the United States of America by 1998, with about 17 percent of global output in 2010–11, from a milk-deficient nation, which doubled milk available per person and increased milk output four-fold, in 30 years,
Relevant evidence: No