Explanation:

- Option 1: D Gukesh

- Gukesh D became the youngest Indian Grandmaster in January 2019, at the age of 12 years, 7 months, and 17 days.

- He was the second-youngest Grandmaster in the world at that time.

- Option 2: R Praggnanandhaa

- He became a Grandmaster at the age of 12 years, 10 months in June 2018.

- He was the youngest Indian Grandmaster before Gukesh.

- Option 3: Parimarjan Negi

- He achieved the Grandmaster title in 2006 at the age of 13.

- For a time, he was the youngest in India until dethroned by later prodigies.

- Option 4: Raunak Sadhwani

- Raunak became a Grandmaster in 2019 but was not the youngest.

Option 1: D Gukesh is correct.

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