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: Microbiology
[{'content': 'A preformed toxin is important in food poisoning due to all EXCEPT - \nSelect and explain. \nA. Staphylococcus aureus, B. Clostridium botulinum, C. ETEC, D. B. cereus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]