The right answer is A) Nuclides of uranium-238 decay over time. They release a huge amount of nuclear energy when their nuclei break apart.
Uranium is a radioactive metal found in the earth's subsoil. Before it can be used as fuel in the reactors of nuclear power plants, it must be extracted and processed.
By using the radioactive properties of uranium, man produces electricity in nuclear power plants. A very educational animation that explains all the steps of the process.