To a good approximation, the equilibrium constant for the reaction

CaCO₃ (s) CaO (s) + CO₂ (g) is written as KP=PCO2,eq (where PCO2,eq is the equilibrium partial pressure of the carbon dioxide). The solids dont appear in the equilibrium constant expression because (select the most appropriate answer)

A. The activities of CaCO₃(s) and CaO(s) are so large they dont change in the reaction.

B. The same amount of CO₂ will always be produced, regardless of how much CaCO₃ we have at the beginning.

C. The activities of CaCO₃(s) and CaO(s) are approximately zero.

D. The reaction will always go to completion because solids and gases dont react with each other.

E. The activities of CaCO₃(s) and CaO(s) are approximately 1.