Explanation:

- The Khelo India Youth Games is a multi-disciplinary sports event held in India.

- The 3rd edition took place in 2020.

- Option 1: Assam hosted the 3rd Khelo India Youth Games in 2020. It was held in Guwahati, and several sports facilities across the state were utilized.

- Option 2: Kerala, known for its beaches and backwaters, has hosted various sporting events, but not this edition of the games.

- Option 3: Karnataka, a key state for sports in India, was not the host for the 3rd edition.

- Option 4: Punjab, known for its rich sporting culture, also did not host these games in 2020.