Among the following the main reactions occurring in the blast furnaces during the extraction of iron from haematite are

i) ${\mathrm{Fe}}_2{\mathrm{O}}_3+3\mathrm{CO}\to 2\mathrm{Fe}+3{\mathrm{CO}}_2$.

ii) $\mathrm{FeO}+{\mathrm{SiO}}_2\to {\mathrm{FeSiO}}_3$

iii) ${\mathrm{Fe}}_2{\mathrm{O}}_3+3\mathrm{C}\to 2\mathrm{Fe}+3\mathrm{CO}$

iv) $\mathrm{CaO}+{\mathrm{SiO}}_2\to {\mathrm{CaSiO}}_3$