JEE Main Chemistry question

What would be the effect on addition of CaCO₃ on the equilibrium of CaCO₃(s) ⇌ CaO(s) + CO₂(g) in a closed container:

• (A)conc. of CO₂ increases
• (B)conc. of CO₂ decreases
• (C)Remains unaffectedCorrect
• (D)Cannot be predicted