Among the following ores Bauxite, Siderite, Cuprite, Calamine, Haematite, Kaolinite, Malachite, Magnetite, Sphalerite, Limonite, Cryolite, the number of principal ores of iron is

Siderite: ${\mathrm{FeCO}}_3$

Malachite: ${\mathrm{CuCO}}_3.\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$

Magnetite: ${\mathrm{Fe}}_3{\mathrm{O}}_4$

Haematite: ${\mathrm{Fe}}_2{\mathrm{O}}_3$

Cryolite: ${\mathrm{Na}}_3{\mathrm{AlF}}_6$

Cuprite: ${\mathrm{Cu}}_2\mathrm{O}$

Limonite: $\mathrm{FeO}\left(\mathrm{OH}\right).{\mathrm{nH}}_2\mathrm{O}$

Kaolinite: $\left[{\mathrm{Al}}_2{\left(\mathrm{OH}\right)}_4{\mathrm{Si}}_2{\mathrm{O}}_5\right]$

Sphalerite: $\mathrm{ZnS}$

Bauxite: ${\mathrm{AlO}}_{\mathrm{x}}{\left(\mathrm{OH}\right)}_{3-2\mathrm{x}}$

So, as we can see that among the given options 4 ores (Siderite, magnetite, Haematite, Limonite) contain iron.