In the context of catalysis, how does an enzyme affect a chemical reaction?

• A. It increases the activation energy so the reaction proceeds more slowly but reaches the same equilibrium position.
• B. It changes the reaction equilibrium by increasing the Gibbs free energy change ($\Delta G$) so more products form at equilibrium.
• C. It lowers the activation energy by stabilizing the transition state, increasing the reaction rate without changing the equilibrium constant.
• D. It is consumed during the reaction, providing energy that drives the reaction to completion.

Answer: (C)