Correct Answer: 

The correct answer is C: Bhagwati Charan Vohra.

Explanation of Options:

Option A: Sukhdev  
 • Incorrect. Sukhdev Thapar was a prominent Indian revolutionary, but he did not write "The Philosophy of the Bomb."
 • He was a close associate of Bhagat Singh and a member of the Hindustan Socialist Republican Association (HSRA).
 • Sukhdev is best known for his involvement in the Lahore Conspiracy Case and his subsequent execution.

Option B: Chandrashekhar Azad  
 • Incorrect. Chandrashekhar Azad was a key figure in the Indian independence movement, but he did not author "The Philosophy of the Bomb."
 • He was a leader of the HSRA and known for his commitment to the cause of Indian independence.
 • Azad is remembered for his bravery and his vow to never be captured alive by the British.

Option C: Bhagwati Charan Vohra  
 • Correct. Bhagwati Charan Vohra was indeed the author of "The Philosophy of the Bomb."
 • He was an influential revolutionary and a member of the HSRA.
 • Vohra wrote this pamphlet to justify the use of revolutionary violence in the struggle for Indian independence.

Option D: Bhagat Singh  
 • Incorrect. Bhagat Singh was a legendary revolutionary, but he did not write "The Philosophy of the Bomb."
 • He was a key member of the HSRA and known for his role in the Lahore Conspiracy Case.
 • Bhagat Singh is celebrated for his writings and ideas, but this particular work was not authored by him.