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': 'Food poisoning occurs in 6-7 hours by all EXCEPT: \nSelect and explain. \nA. Staphylococcus, B. E. coli, C. Clostridium, D. Bacillus cereus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: E. coli REF: See APPENDIX-22 for "Acute infectious diarrhea"', 'role': 'assistant'}]