Roughly 80 g of Fe2O3 was present in Experiment 3, and upon completion ... ...

Roughly 80 g of Fe2O3 was present in Experiment 3, and upon completion of the reaction, it was measured that 22 g of CO2 was formed. If this is true, how much CO must have reacted before reaching completion of the reaction?  
(A) 14 grams
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in 02. Chemical Reactions