Step 1: Question Interpretation.
The query concerns the geographical placement of the planet's sole national park that floats.
Step 2: Option Analysis.
- Option A: Tripura lacks a floating national park. - Option B: Jharkhand does not contain a floating national park. - Option C: Accurate. Keibul Lamjao, the world's unique floating national park, is situated in Manipur, India. - Option D: Assam hosts Kaziranga and other parks, but not a floating national park. - Option E: Chhattisgarh also does not possess a floating national park.
Step 3: Resolution.
Manipur is identified as the correct location.
Final Answer: \[\boxed{\text{C}}\]