Answer : 4. "तमिलनाडु"
Explanation :

The Tamil Nadu Forest Department has begun a three-day elephant census at Sathyamangalam Tiger Reserve. Located at the Eastern and Western Ghats junction in Erode district of Tamil Nadu, the reserve is part of the Nilgiri Biosphere Reserve. It is adjacent to Mudumalai, Bandipur and Biligiri Rangaswamy Temple Tiger Reserves, which collectively have over 280 tigers, the world's largest tiger population. Declared a tiger reserve in 2013, it connects the Eastern and Western Ghats, supporting diverse wildlife.