Option 1 - Bhagat Singh: Bhagat Singh was a revolutionary and a freedom fighter in India. While he was involved in the fight for independence, there is no record or evidence to suggest that he authored the book "Philosophy of the Bomb." Therefore, option 1 is incorrect.

Option 2 - Jawaharlal Nehru: Jawaharlal Nehru was the first Prime Minister of India and a prominent leader in the Indian independence movement. However, there is no information or evidence to suggest that he was one of the authors of the book "Philosophy of the Bomb." Therefore, option 2 is incorrect.

Option 3 - Surya Sen: Surya Sen, also known as Masterda, was a revolutionary leader in the Indian freedom struggle. He played a significant role in the Chittagong Armory Raid of 1930. However, there is no connection or evidence to suggest that he was one of the authors of the book "Philosophy of the Bomb." Therefore, option 3 is incorrect.

Option 4 - Yashpal: Yashpal is the correct answer. He was a renowned Hindi writer, novelist, and essayist. Yashpal was one of the authors of the