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: Social & Preventive Medicine
[{'content': 'Incubation period of salmonella in food poisoning \nSelect and explain. \nA. 1-6 hours, B. 12-24 hours, C. 1-2 days, D. 6-12 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]