The correct option is A 1973
The Silent Valley movement started in 1973 to protect the Silent Valley reserve forest. The protest went on for over ten years and involved thousands of people. In 1976, Kerala Sasthra Sahitya Parishad (KSSP), the largest popular-science organisation in Kerala, also joined the protest. They helped in mobilising people by publishing their reports on the ecological, economical, and social impacts of the hydroelectric project.