Which one of the following is the national aquatic animal of India?

1. The question asks to identify the national aquatic animal of India. 2. The Government of India declared the Gangetic dolphin (Platanista gangetica gangetica) as the National Aquatic Animal on 5th October 2009. 3. The Gangetic dolphin is a freshwater dolphin species primarily found in the Ganga-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of India, Nepal, and Bangladesh. 4. Option (A) Saltwater crocodile is a large reptile found in coastal regions and estuaries. 5. Option (B) Olive ridley turtle is a species of sea turtle found in warm tropical waters. 6. Option (D) Gharial is a critically endangered, fish-eating crocodile species found in some rivers of the northern Indian subcontinent. 7. Therefore, the correct answer is Gangetic dolphin.