How Do Competitive and Noncompetitive Enzyme Inhibitors Differ

How do competitive and noncompetitive enzyme inhibitors differ?

A) Competitive inhibitors bind to the active site,whereas noncompetitive inhibitors may change the shape of the active site.
B) Competitive inhibitors have a higher energy of activation than noncompetitive inhibitors.
C) Competitive and noncompetitive inhibitors function at different pH values.
D) Noncompetitive inhibitors contain magnesium,whereas competitive inhibitors contain iron.
E) Noncompetitive inhibitors are reversible,whereas competitive inhibitors are irreversible.