In the dissociation of $CaC{O}_3$ in a closed vessel, the forward reaction is favored by

The reaction, $CaCO\rightleftharpoons CaO+ C{O}_2\left(g\right)$ in line with the Le Chatelier Principle the equilibrium, will shift ahead such that more carbon dioxide is generated when the pressure is decreased by removing some carbon dioxide. By doing this, the system's stress will be eliminated. The forward reaction is therefore preferred.

Therefore, the correct answer is option (D) removing $C{O}_2$.