Which one among the following Biosphere Reserves is spread over three states in India ?

The Nilgiri Biosphere Reserve is the only reserve among the given options that is spread over three Indian states: Tamil Nadu, Kerala, and Karnataka [1]. Established in 1986, it was India's first biosphere reserve and is part of the UNESCO World Network of Biosphere Reserves. In contrast, the other options are more geographically restricted. Dehang-Debang is located entirely within Arunachal Pradesh [3]. Nokrek is situated in the state of Meghalaya and is noted as one of the smallest reserves. Seshachalam Hills Biosphere Reserve is located in Andhra Pradesh [2]. The Nilgiri reserve encompasses several protected areas across the three states, including Bandipur, Mudumalai, and Wayanad, making it a critical trans-boundary conservation zone in the Western Ghats.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > zoning of Biosphere reserves > p. 37
2. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 5: Natural Vegetation and National Parks > Table 5.8 > p. 50
3. [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 5: Natural Vegetation and National Parks > BIOSPHERE RESERVES > p. 49