The correct statement among the following regarding the reaction of FeO below point A in the above diagram is

1. Reduced by carbon monoxide only.

2. Reduced by both carbon monoxide and carbon.

3. Reduced by carbon only.

4. Not  reduced by both carbon and carbon monoxide.

HINT: Below point ‘A’ FeO can be reduced by carbon monoxide only.
Any metal will reduce oxide of other metals which lie above it in the Ellingham diagram because free energy change will become more negative.
Below point A Gibbs free energy change for the formation of CO2 from CO GCO,CO2° has lower value (more negative value) than Gibbs free energy change for the formation of FeO GFe,FeO.
Hence, FeO will be reduced by CO only below point A.