This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
The drug which inhibits the rate-limiting step of acetylcholine synthesis is 
Select and explain. 
A. Vesamicol, B. Hemicholinium, C. Botulinum toxin, D. Cocaine
B: Hemicholinium
Answer: B: Hemicholinium 
Explanation: Rate limiting step is mediated by choline acetyltransferase which is blocked by hemicholinium. Ref: KD T ripathi 8th ed.