This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacterial infection, Subject name: Medicine
[{'content': 'Among the toxins produced by Clostridium botulinum, the most potent is: \nSelect and explain. \nA. A, B. C, C. D, D. F', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Eight antigenically distinct C. botulinum toxins are known:- A, B, C (alpha), C (beta), D, E, F, and G. Types A, B, E, and, rarely, F cause human disease. Toxins A and B are the most potent, and the consumption of small amounts of food contaminated with these types has resulted in full-blown disease. During the last 20 years, toxin A has been the most common cause of food borne outbreaks; toxins B and E follow in frequency. Toxins C and D cause disease in various animals.', 'role': 'assistant'}]