The common impurities present in bauxite are:

a. $\mathrm{CuO}$

b. $\mathrm{ZnO}$

c. ${\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$

d. ${\mathrm{SiO}}_{2}$

Choose the correct option:
1. a and b
2. b and c
3. c and d
4. a and d

HINT: Bauxite is an ore of Al.
Explanation:
Bauxite, rock largely composed of a mixture of hydrous aluminum oxides. Bauxite is the principal ore of aluminum.
Bauxite is an ore of aluminium which contain ${\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ and ${\mathrm{SiO}}_{2}$ as common impurities.