Explanation:

An ore is a naturally occurring rock or sediment that contains one or more valuable minerals, typically metals, that can be mined, treated, and sold at a profit. Bauxite is the world's main source of aluminium. It is a sedimentary rock with a relatively high aluminium content, composed primarily of aluminium hydroxide minerals, mainly gibbsite ($\text{Al(OH)}_3$), boehmite ($\gamma\text{-AlO(OH)}$), and diaspore ($\alpha\text{-AlO(OH)}$). Option (C) is correct because bauxite is the principal ore from which aluminium metal is extracted. Option (A) is incorrect; Iron is primarily extracted from ores like hematite ($\text{Fe}_2\text{O}_3$) and magnetite ($\text{Fe}_3\text{O}_4$). Option (B) is incorrect; Zinc is typically extracted from ores like sphalerite ($\text{ZnS}$) and smithsonite ($\text{ZnCO}_3$). Option (D) is incorrect; Silver is usually found in native form or in ores like argentite ($\text{Ag}_2\text{S}$) and pyrargyrite ($\text{Ag}_3\text{SbS}_3$).