Option 1 -> Wild Ass are primarily found in the Little Rann of Kutch, Gujarat, not in Kaziranga.
Option 2 -> Kaziranga is world-famous for hosting the largest population of the endangered One-horned Rhinoceros.
Option 3 -> While elephants are present in Kaziranga, the park is not specifically known for them as they're found across many Indian forests.
Option 4 -> Gharials are river-dwelling crocodilians found mainly in the Chambal and other river systems, not specifically in Kaziranga.
Hence, Option 2: One-horned Rhinoceros -> Kaziranga National Park in Assam is a UNESCO World Heritage Site and hosts approximately two-thirds of the world's Great One-horned Rhinoceros population, making it the species' most important stronghold -> correct