Chipko movement is a public agitation that occurred in

Mansbal area in Kashmir
Silent valley in Kerala
Sundarban area in Bengal
Tehri Garhwal area of Uttar Pradesh

The correct answer is D. Tehri Garhwal area of Uttar Pradesh.

The Chipko movement was a forest conservation movement that started in the Garhwal Himalayas of India in the 1970s. The movement was started by a group of women who protested against the felling of trees in their village. The women hugged the trees to prevent them from being cut down, and this act of defiance became a symbol of the movement.

The Chipko movement was successful in preventing the felling of trees in many areas, and it also helped to raise awareness about the importance of forests. The movement has been credited with helping to change the way that forests are managed in India, and it has inspired similar movements around the world.

The other options are incorrect because they are not areas where the Chipko movement occurred. Mansbal area in Kashmir is a tourist destination, Silent valley in Kerala is a national park, and Sundarban area in Bengal is a delta region.