Explanation:

- Option 1: Vir Sanghvi

- Vir Sanghvi is a prominent Indian journalist, columnist, and talk show host known for his work in both print and broadcast media. However, he did not author an autobiography titled "Devil’s Advocate: The Untold Story."

- Option 2: Pranoy Roy

- Pranoy Roy is an Indian journalist and the co-founder of NDTV. He is a well-known figure in the Indian media landscape, but he is not the author of "Devil’s Advocate: The Untold Story."

- Option 3: Vinod Dua

- Vinod Dua was a veteran Indian journalist best known for his work on television news and various socio-political shows. He is not associated with the autobiography "Devil’s Advocate: The Untold Story."

- Option 4: Karan Thapar

- Correct Answer: Karan Thapar, an Indian journalist known for his incisive interviewing style, is the author of the autobiography "Devil’s Advocate: The Untold Story." The title reflects his reputation for asking challenging questions, often playing the 'devil's advocate' in interviews.

The correct answer is Option 4: Karan Thapar.