Correct Answer:
B. J. Robert Oppenheimer
The correct answer is J. Robert Oppenheimer. J. Robert Oppenheimer is widely known as the "Father of the Atomic Bomb" for his role as the scientific director of the Manhattan Project during World War II. He oversaw the development of the first nuclear weapons. Among the options:
- Albert Einstein: His theory (E=mc²) laid the foundation, but he did not directly build the bomb.
- J. Robert Oppenheimer: Correct; he is the "Father of the Atomic Bomb".
- Enrico Fermi: Built the first nuclear reactor (Chicago Pile‑1) but is not known as the "Father of the Atomic Bomb".
- Niels Bohr: Contributed to atomic structure and quantum theory but was not the director of the Manhattan Project.
Hence, the correct answer is "J. Robert Oppenheimer".