Correct Answer - 2
At 500-800 K (lower temperature range in the blast furnace)
`3Fe_2O_3+COto2Fe_3O_4+CO_2`
`Fe_3O_4+CO to 3Fe+ 4 CO_2`
`Fe_2O_3 + CO to 2FeO+ CO_2`
At 900-1500 K (higher temperature range in the blast furnace):
`C+CO_2 to 2CO, FeO+CO to Fe+CO_2`