Right answer is (b) Bauxite
The explanation is: Bauxite is the chief ore of aluminium. The composition of bauxite is Al2O3.2H2O, it’s a mixture of hydrated iron oxide and hydrated aluminium oxide. Kaolinite is another ore of aluminium but its less availability is less compare to bauxite and the extraction of aluminium from kaolinite is a hard process and costs more.