Answer : 2. "सरदार बलदेव सिंह"
Explanation :

Sardar Baldev Singh was the first Defence Minister of India. He held this position in the Cabinet of Prime Minister Jawaharlal Nehru when the Ministry of Defence was established after India gained independence in 1947. Sardar Baldev Singh played a crucial role in the early years of independent India in organizing and managing the defense structure of the country. His tenure as Defence Minister contributed to the establishment and development of the Indian armed forces.