This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which one of the following drugs is not a reversible anticholinesterase drug? 
Select and explain. 
A. Edrophonium, B. Demecarium, C. Carbaryl, D. Twine
C: Carbaryl
Answer: C: Carbaryl 
Explanation: None