Step 1: Identifying the correct option:
M. S. Swaminathan is internationally recognised as the "Father of the Green Revolution" in India. In the 1960s he led the introduction of high-yielding variety (HYV) wheat and rice seeds, along with chemical fertilisers and irrigation, which transformed India from a food-deficit to a food-surplus nation.
Step 2: Why the other options are wrong:
Nehru shaped India's early industrial and scientific-temper policy but is not linked to agricultural science reforms. Patel is remembered for integrating the princely states. Gandhi championed rural self-reliance and khadi, not HYV agricultural technology.
Final Answer:
M. S. Swaminathan (Option B)