Which of the following scenarios best illustrates noncompetitive inhibition in a biological system?

• A. A drug binds to the active site of an enzyme, preventing substrate binding.
• B. A toxin binds to an allosteric site on an enzyme, reducing its activity regardless of substrate concentration.
• C. A substrate competes with an inhibitor for the active site of an enzyme.
• D. An enzyme is denatured by heat, losing its activity.

Answer: (B)