In enzyme catalysis, what is the primary effect of an enzyme on a chemical reaction?

• A. It changes the reaction equilibrium constant by decreasing the Gibbs free energy change $\Delta G$ of the overall reaction.
• B. It lowers the activation energy by stabilizing the transition state, increasing the reaction rate without changing the reaction equilibrium.
• C. It is consumed during the reaction, shifting the equilibrium toward products as enzyme concentration decreases.
• D. It increases the activation energy so that only high-energy substrates can react, slowing the reaction rate.

Answer: (B)