Correct option is B
The correct one-word substitution for the given phrase is "Traitor."
- Traitor: A person who betrays their country, cause, or trust (देशद्रोही).
- Example Sentence: The soldier was declared a traitor for leaking classified information to the enemy.
Meanings of other given options and why they are incorrect:
- Mascot: A person or thing that is supposed to bring good luck (शुभंकर).
- Icon: A person or thing regarded as a representative symbol (प्रतिमा).
- Paragon: A person or thing regarded as a perfect example of a particular quality (उत्तमउदाहरण).