Detailed Explanation:

Answer: Option 4 — Western Ghats

The Great Indian Hornbill (Buceros bicornis) is a large frugivorous bird native to the dense evergreen and moist deciduous forests of India. Its natural habitat in India is primarily concentrated in the Western Ghats, where it thrives in the tropical rainforests with abundant fruit-bearing trees. The bird is also found in the foothills of the Himalayas in the northeastern states, but among the given options, the Western Ghats is the correct answer. The species requires tall trees for nesting and roosting, making the sand deserts of northwest India, higher cold Himalayas of Jammu and Kashmir, and salt marshes of Gujarat unsuitable habitats. It is listed as vulnerable due to habitat loss and hunting pressure.