“India has the largest population of the Asian X. Today, there are just about 20,000 to 25,000 X in their natural habitat spreading across the evergreen forests, dry thorn forests, swamps and grasslands. Their prime habitats are, however, the moist deciduous forests. The X population in India ranges from North-West India where they are found in the forest divisions of Dehradun, Bijnor and Nainital districts of UP to the Western Ghats in the states of Karnataka and Kerala and in Tamil Nadu. In Central India, their population is distributed in southern Bihar and Orissa. In the East, they are seen in North-Bengal, Assam and a few other states.” The animal ‘X’ referred to in this quotation is

The quoted passage—noting about 20,000–25,000 animals across evergreen, moist-deciduous, dry thorn forests, swamps and grasslands and a range from NW India to the Western Ghats, central India, North Bengal and Assam—matches the Asian elephant (Elephas maximus). India harbors roughly 25,000 wild Asian elephants and holds more than half of the global Asian elephant population, which aligns with the “largest population” phrasing [1]. Protected areas in North Bengal and Assam (e.g., Jaldapara, Kaziranga) explicitly list elephants among dominant species, corroborating the cited eastern distribution [2]. Lions, rhinos and tigers have far more restricted or different population magnitudes and ranges in India, so the correct choice is Elephant.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 16: Conservation Efforts > The campaign mascot ,Gaju,. > p. 234
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > Table 4.10 (Contd.) > p. 39