The correct answer is option 4, Arunachal Pradesh. Namdhapa National Park is located in the state of Arunachal Pradesh, which is in the northeastern part of India. It is one of the largest protected areas in the region and is known for its rich biodiversity. The park is situated on the eastern Himalayas and covers an area of about 1,985 square kilometers. It is home to several endangered species including the snow leopard, clouded leopard, and red panda. The park also has a diverse range of flora and fauna, with dense forests, alpine meadows, and snow-capped peaks. It is a popular destination for wildlife enthusiasts and nature lovers.