This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Average incubation period of typhoid is: \nSelect and explain. \nA. 2-3 days, B. 5-8 days, C. 10-15 days, D. 15-30 days', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. (c) 10-15 daysRef: Harrison's 18th ed ch-15211.", 'role': 'assistant'}]