The correct option is (c).
Explanation
The Ganga-Brahmaputra basin supports a diverse range of wildlife due to its varied topography, ranging from the plains to the deltaic regions.
Statement 1 is Incorrect. The one-horned rhinoceros is not found in the Sundarbans delta. It is primarily found in the Brahmaputra plains, particularly in Assam (e.g., Kaziranga National Park). The Sundarbans is a mangrove ecosystem not suitable for the one-horned rhinoceros.
Statement 2 is Correct. The Sundarbans delta is the famous natural habitat of the Royal Bengal Tiger. Additionally, reptiles such as crocodiles and alligators are found in the river waters and estuarine environments of this region.
Statement 3 is Correct. The aquatic life in the fresh river waters, lakes, and the Bay of Bengal is abundant. The most popular varieties of fish found in this basin include rohu, catla, and hilsa. Fish and rice constitute the staple diet of the people living in this area.
Key Takeaway: The one-horned rhinoceros is endemic to the Brahmaputra plains, while the Royal Bengal Tiger is the apex predator of the Sundarbans delta.