The correct answer is C. Electrolysis.
Aluminium is a highly reactive metal that is difficult to extract from its ores. The most common method of extracting aluminium is by electrolysis. In this process, a molten mixture of aluminium oxide and cryolite is electrolyzed, with aluminium ions being reduced at the cathode and oxygen gas being evolved at the anode.
Oxidation is a chemical reaction in which an element or compound loses electrons. This can be a spontaneous process, or it can be driven by an external source of energy, such as heat or electricity. Oxidation is often used to purify metals, as it can remove impurities from the surface of the metal.
Distillation is a separation process that is used to purify liquids. In distillation, a liquid is heated until it vaporizes. The vapor is then condensed back into a liquid, and the impurities are left behind. Distillation is often used to purify water, alcohol, and other liquids.
Ozonolysis is a chemical reaction in which ozone is used to break down organic compounds. Ozonolysis is often used to purify air and water, and it is also used in the production of certain chemicals.
In conclusion, the correct answer is C. Electrolysis.