The correct statement for the reduction of FeO at the temperature corresponding to point D is: 
 

  

1. ∆G value for the overall reduction reaction with carbon monoxide is zero.
2. ∆G value for the overall reduction reaction with a mixture of 1 mol carbon, and 1 mol oxygen is positive.
3. ∆G value for the overall reduction reaction with a mixture of 2 mol of carbon, and 1 mol of oxygen will be positive.
4. ∆G value for the overall reduction reaction with carbon monoxide is negative.

HINT: See the Ellingham diagram.
Explanation:
At point D, the G curve for the formation of CO2 from CO and FeO from Fe intersect with each other, therefore, the ΔG value for the overall reduction reaction with carbon monoxide is zero. 
Hence, (1) is the correct choice.