4. Potassium chromate is produced by the reaction of solid chromite ore $(\mathrm{FeCr_2O_4})$ with solid potassium carbonate and gaseous oxygen at high temperatures. The other products of the reaction are solid iron(III) oxide and gaseous carbon dioxide. In a particular experiment $169~\mathrm{kg}$ of chromite ore, $298~\mathrm{kg}$ of potassium carbonate, and $150~\mathrm{kg}$ of oxygen were sealed in a reaction vessel and reacted at a high temperature.

a FeCr₂O₄ (s) + b K₂CO₃ (s) + c O₂ (g) → d K₂CrO₄ (s) + e Fe₂O₃ (s) + f CO₂ (g)

Which compound is the limiting reagent?
(A) O₂
(B) K₂CO₃
(C) K₂CrO₄
(D) Fe₂O₃
(E) FeCr₂O₄