Which one of the following statements regarding enzyme inhibition is correct?

• A
  Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.
• B
  Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.
• C
  Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.
• D
  Non-competitive inhibitors often bind to the enzyme irreversibly.