Which of the Following Statements Regarding Enzyme Regulation Is Correct

Which of the following statements regarding enzyme regulation is correct?

A) Addition of an inhibitor to a V system results in kinetics similar to addition of a competitive inhibitor to a typical hyperbolic system.
B) Allosteric effectors are always more powerful than covalent modification.
C) Addition of an allosteric activator to a K system changes the plot of V versus [S] from a sigmoidal curve to a more hyperbolic curve.
D) The T state of an enzyme generally has more activity than the R state.