This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
Which of the following anti-Parkinson drugs acts by decreasing brain cholinergic activity 
Select and explain. 
A. Levodopa, B. Benserazide, C. Selegiline, D. Biperiden
D: Biperiden
Answer: D: Biperiden 
Explanation: An antiparkinson medication is a type of drug which is intended to treat and relieve the symptoms of Parkinson's disease. Most of these agents act by either increasing dopamine activity or reducing acetylcholine activity in the central nervous system. Ref: KD Tripathi 8th ed.