Which Statement Is True About How Drugs for Parkinson's Disease

Which statement is true about how drugs for Parkinson's disease work?

A) Dopaminergic drugs decrease the amount of dopamine activity in the brain.
B) COMT inhibitors allow a larger amount of levodopa to reach the brain,which lowers the brain's dopamine levels.
C) MAO-B inhibitors facilitate the enzyme monoamine oxidase B that breaks down dopamine in the brain.
D) Anticholinergic drugs block cholinergic nerve impulses to minimize tremors and rigidity.