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
[{'content': 'Botulin acts by: \nSelect and explain. \nA. Secretion of Ach, B. 1Synthesis of Ach, C. Inhibits Ach release, D. Muscle nerve block', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Inhibits Ach release', 'role': 'assistant'}]