Explanation:

Here’s the breakdown:

- Option 1: Jharkhand – Doesn’t really fit. Onam’s roots aren’t here. Jharkhand has its own unique tribal festivals.

- Option 2: Manipur – Again, not the origin of Onam. Manipur is in northeastern India with a totally different festival scene.

- Option 3: Kerala – This is the one. Onam is deeply connected with Kerala’s culture and legends, especially the story of king Mahabali. It’s their biggest festival.

- Option 4: Mizoram – Not connected to Onam at all. Mizoram celebrates different, local festivals.

So, to sum it up, the correct answer is Option 3: Kerala.