How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?

• A. By binding to the active site of the enzyme, thus preventing binding of the normal substrate.
• B. By binding to an allosteric site, thus changing the shape of the active site of the enzyme.
• C. By decreasing the free-energy change of the reaction catalyzed by the enzyme.
• D. By binding to the substrate, thus changing its shape so that it no longer binds to the active site of the enzyme.