Explanation:

- Option 1: Ox. While oxen are common in India, they are not the state animal of Assam.

- Option 2: One-horned Rhino. This is indeed the state animal of Assam. Assam is known for its rich wildlife, especially the Kaziranga National Park where the majority of India's one-horned rhinos are found.

- Option 3: Elephant. These majestic creatures are often associated with Indian culture but are not the state animal of Assam.

- Option 4: Snow Leopard. These are found in the Himalayas and are not native to Assam.