Option 1: Dr. Vikram Sarabhai was the father of India's space program, not primarily associated with nuclear reactor development.
Option 2: Dr. Abdul Kalam was known as the Missile Man of India and contributed to missile and space technology, not nuclear reactors.
Option 3: Dr. Raja Ramanna was a key nuclear scientist who led India's first nuclear test in 1974, but wasn't the pioneer of the first reactor.
Option 4: Dr. Homi Jehangir Bhabha founded India's nuclear program and established the country's first nuclear reactor.
Dr. Homi Jehangir Bhabha is regarded as the father of India's nuclear program and was instrumental in establishing Apsara, India's first indigenous nuclear research reactor, which became operational in 1956 at the Bhabha Atomic Research Centre.
Correct Answer: Dr. Homi Jehangir Bhabha