Pair 1 is Correct: The Blue-finned Mahseer is a freshwater fish species that is naturally found in the Cauvery River. This species is also found in other rivers of the Deccan Plateau. Pair 2 is incorrect: The Irrawaddy Dolphin is not found in the Chambal River, which is known for the Gangetic Dolphin. It is found in coastal areas in South and Southeast Asia, and in three rivers: the Ayeyarwady (Myanmar), the Mahakam (Indonesian Borneo) and the Mekong (Cambodia and Laos). In India, it is found in Lake Chilika (Odisha). Pair 3 is correct: The Rusty-spotted Cat is a small wild cat species that is found in the Eastern Ghats. It is also found in the Western Ghats, central India, and Sri Lanka. Therefore, option (C) 1 and 3 are correctly matched.