In a reaction where the concentration of reactant A is decreased below its equilibrium concentration, what will happen to restore equilibrium?

• A. The reaction will stop until the concentration of A increases naturally.
• B. The equilibrium constant will change to accommodate the new concentration.
• C. The reaction will proceed in the forward direction to decrease the concentration of A.
• D. The reaction will proceed in the reverse direction to increase the concentration of A.

Answer: (D)