Explanation:

- Option 1: Amitav Ghosh

- An Indian author known for works like "The Glass Palace" and "Sea of Poppies."

- Not associated with "Autobiography of an Unknown Indian."

- Option 2: Vikram Seth

- Renowned for his epic novel "A Suitable Boy."

- Does not have any known connection to the memoir in question.

- Option 3: Nirad C Chaudhuri

- Correct Answer: This Indian author wrote "Autobiography of an Unknown Indian."

- The book is a detailed account of his early life and experiences in British India.

- Option 4: Salman Rushdie

- Famous for works like "Midnight's Children" and "The Satanic Verses."

- Not linked to the title "Autobiography of an Unknown Indian."

The correct answer is Option 3: Nirad C Chaudhuri.