Why Correct: Sardar Vallabhbhai Patel served as India's first Deputy Prime Minister from 1947 to 1950 under Prime Minister Jawaharlal Nehru, while also holding the Home Minister portfolio.
Distractor Analysis: L. K. Advani served as Deputy Prime Minister from 2002 to 2004 under Atal Bihari Vajpayee. Morarji Desai served as Deputy Prime Minister from 1967 to 1969 under Indira Gandhi. Charan Singh served as Deputy Prime Minister from 1979 to 1980 under Morarji Desai and later became Prime Minister.
Takeaway: Patel earned the title "Iron Man of India" for integrating over 500 princely states into the Indian Union after independence.