Which of the following biosphere reserves is not recognized internationally by UNESCO?

Correct option is E

All the listed biosphere reserves are recognized internationally by UNESCO. The Nilgiri Biosphere Reserve, which was the first biosphere reserve in India, was included in the UNESCO World Network of Biosphere Reserves in 2000. The Sundarbans Biosphere Reserve, known for its unique mangrove forests, was also recognized by UNESCO. Similarly, the Gulf of Mannar Biosphere Reserve, which is rich in marine biodiversity, has been part of the UNESCO network. Therefore, none of the options listed above is correct, as all these biosphere reserves have international recognition by UNESCO, highlighting the global significance of these sites in terms of conservation, research, and sustainable development.