Answer:

Introduction:
Nuclear power stations generate electricity by harnessing the energy released from nuclear reactions. These reactions occur in the reactor core, where a fuel is used to generate heat. This heat is then used to produce steam, which drives a turbine connected to a generator, ultimately generating electricity. The fuel used in nuclear power stations is typically a mineral that contains a radioactive element.

Explanation:
Among the given options, pitchblende (option D) is the mineral that is used as a fuel in nuclear power stations. Here's why:

Pitchblende:
1. Pitchblende is a form of uranium ore that is primarily composed of the mineral uraninite. Uraninite is a rich source of uranium, a radioactive element.
2. Uranium-235 (U-235) is the isotope of uranium that is primarily used as fuel in nuclear reactors. It is a fissile material, meaning it can sustain a nuclear chain reaction.
3. Pitchblende contains a relatively high concentration of U-235, making it a suitable fuel for nuclear power stations.
4. The process of nuclear fission occurs in the reactor core, where U-235 atoms are bombarded with neutrons, causing them to split and release a tremendous amount of energy in the form of heat.
5. This heat is used to produce steam, which drives a turbine connected to a generator, ultimately generating electricity.

Other options:
1. Bauxite (option A) is an ore of aluminum and is not used as a fuel in nuclear power stations.
2. Quartz (option B) is a mineral composed of silicon and oxygen, and it is not used as a fuel in nuclear power stations.
3. Feldspar (option C) is a group of minerals that are commonly found in rocks, but they are not used as a fuel in nuclear power stations.

Conclusion:
In conclusion, pitchblende (option D) is the mineral that is used as a fuel in nuclear power stations. It contains uranium-235, which undergoes nuclear fission to produce heat energy, ultimately generating electricity.