Explanation:

- The Sahitya Akademi Award is a prestigious recognition in Indian literature, honoring outstanding works in various Indian languages.

- Shashi Tharoor is well-known for his eloquent writing and his work *An Era of Darkness: The British Empire in India* critically examines the impact of British colonialism on India.

- Option 2: Shashi Tharoor - Correct. His in-depth historical analysis won the Sahitya Akademi Award in 2019.

- Option 1: Ramachandra Guha is a renowned historian, but he did not win the award for this book.

- Option 3: Romila Thapar is a respected historian in Indian history, not associated with this title.

- Option 4: Vikram Seth, a celebrated author, is best known for work in fiction and poetry, not this work.