Which of the following best explains the effects of a catalyst on the rate of a reversible reaction?

Explanation

A catalyst affects the rate of a reversible reaction by providing an alternative pathway with a lower activation energy, thereby increasing the rate at which equilibrium is reached. It does not change the equilibrium position or selectively affect the forward or reverse reaction rates differently. Option D is correct because it accurately describes the role of a catalyst in reaction kinetics. Option A is incorrect because a catalyst speeds up both forward and reverse reactions equally, not just one. Option B is incorrect because a catalyst does not change the kinetic energy of the reacting molecules. Option C is incorrect because the equilibrium position remains unchanged by a catalyst; it only affects the rate of reaching equilibrium.