Calcium oxide and carbon dioxide combine to form calcium carbonate in the reversible reaction:

CaO + CO2 ⇌ CaCO3

When the reaction is at dynamic equilibrium, which statement must be true?

(1 point)
Responses

The forward and reverse reactions have stopped.
The forward and reverse reactions have stopped.

The reaction has run out of carbon dioxide or calcium oxide.
The reaction has run out of carbon dioxide or calcium oxide.

The concentration of calcium carbonate is increasing.
The concentration of calcium carbonate is increasing.

Calcium carbonate and calcium oxide are formed at the same rate.

The forward and reverse reactions are occurring at the same rate.