Correct Answer: Cryolite

Solution : The correct option is Cryolite .

Cryolite is a mineral that was once used in the aluminium extraction process but is no longer widely used. It has the chemical formula Na ₃ AlF ₆ , which indicates that it comprises sodium, aluminium, and fluoride ions. Cryolite has a low melting point, making it useful as a flux in the electrolytic reduction process used to obtain aluminium metal from its source, bauxite.