The correct answer is: d) Rich riverine biodiversity.
The Lohit River is a tributary of the Brahmaputra River in India. It flows through the state of Arunachal Pradesh, which is known for its rich riverine biodiversity. The river is home to a variety of fish species, including the endangered golden mahseer. It is also home to a number of other animals, including elephants, tigers, and rhinoceroses. The river is a popular destination for fishing and wildlife tourism.
Option a) is incorrect because adventure tourism is not a major activity in the Lohit River valley. Option b) is incorrect because tea plantations are not a major feature of the Lohit River valley. Option c) is incorrect because wildlife sanctuaries are not a major feature of the Lohit River valley.