Correct Definition of Competitive Inhibition

What is the most correct definition of competitive inhibition?

A. Another enzyme completes the same reaction and uses the available reactant.

B. An inhibitor binds directly to the active site and prevents the reactant from binding.

C. A metal cofactor prevents the binding of the reactant by binding at the active site.

D. An inhibitor binds to the enzyme at a binding site, and prevents the enzyme from catalyzing the reaction.

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