The correct answer is b) The discovery of nuclear fission.

Explanation:
During the 1930s, German scientists made significant contributions to the field of nuclear physics, specifically in the area of nuclear fission. Nuclear fission is the process in which the nucleus of an atom is split into two smaller nuclei, releasing a large amount of energy in the process.

Key Points:
- German scientists Otto Hahn, Fritz Strassmann, and Lise Meitner were at the forefront of this discovery.
- In 1938, Otto Hahn and Fritz Strassmann conducted experiments where they bombarded uranium atoms with neutrons and discovered that the uranium nucleus could split into two smaller nuclei. They also noticed that the total mass of the resulting nuclei was slightly smaller than the original uranium nucleus.
- Lise Meitner, who had fled Germany due to her Jewish background, collaborated with her nephew Otto Frisch, and together they explained the phenomenon of nuclear fission.
- They theorized that when the uranium nucleus absorbs a neutron, it becomes unstable and splits into two smaller nuclei, releasing a large amount of energy in the process. This energy is what powers nuclear reactors and atomic bombs.
- This discovery had profound implications for both peaceful and military applications. It paved the way for the development of nuclear power, which can generate electricity without the need for fossil fuels. However, it also provided the knowledge necessary for the creation of atomic bombs.
- The Nazis recognized the potential military applications of nuclear fission and initiated a research program known as the Uranverein (Uranium Club). This program aimed to develop atomic weapons during World War II.
- However, due to various challenges, including limited resources, internal disputes, and the eventual defeat of Germany in the war, the Nazis were unsuccessful in building an atomic bomb.

In conclusion, the Nazis in Germany made the discovery of nuclear fission, which had significant implications for both peaceful and military applications. While they recognized its potential for developing atomic weapons, they were ultimately unsuccessful in their efforts.

Option (b)