How Does the Drug Tolcapone Relieve the Symptoms of Parkinson

How does the drug tolcapone relieve the symptoms of Parkinson disease?

A) Acts as a dopamine agonist, replacing the activity of dopamine
B) Forces the substantia nigra to increase the production and release of natural dopamine
C) Suppresses the activity of an enzyme that normally breaks down naturally occurring dopamine
D) Increases the number of dopamine receptors sites throughout the central nervous system, thus increasing the effectiveness of dopamine and dopamine agonists