The correct answer is (b), Rajendra Singh.
Rajendra Singh is a water conservationist who is known as the “Waterman of India”. He has been working to revive traditional water harvesting systems in India for over 30 years. He has helped to restore over 1,000 water bodies and has inspired millions of people to take action to conserve water.
Sundar Lal Bahuguna was an environmental activist who is known for his work to protect the Himalayas. He was a key figure in the Chipko movement, which protested against deforestation in the Himalayas. He was also a member of the National Ganga River Basin Authority.
Ramdev Mishra was a social worker who is known for his work to improve the lives of people in rural India. He founded the Sarva Seva Sangh, a non-profit organization that works in the areas of education, health, and agriculture.
Baba Amte was a social worker who is known for his work with people with disabilities. He founded the Anandvan ashram, a home for people with disabilities. He was also a recipient of the Ramon Magsaysay Award.