Step 1: Understand the significance of Kaziranga National Park.
Kaziranga National Park, located in Assam, India, is famous for its population of one-horned rhinoceroses.
Step 2: Review the options.
- Lions are not found in Kaziranga National Park, as it is not their natural habitat.
- Tigers are found in Kaziranga, but the park is most famous for the rhinoceros population.
- Panthers are not specifically associated with Kaziranga.
- Rhinoceros are the iconic species of Kaziranga, and the park is home to the largest population of one-horned rhinoceroses.
Step 3: Conclude.
Kaziranga National Park is most famous for its population of rhinoceroses, making option (D) the correct answer.
Final Answer:
\[
\boxed{\text{Rhinoceros}}
\]