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 chancroid is: \nSelect and explain. \nA. < 7 days, B. 10-14 days, C. 2-3 weeks, D. 3-4 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Chancroid: caused by Hemophilus ducreyi Incubation period is 4 to 7 days Azithromycin is drug of choice Ref: Park 21st edition, page 305.', 'role': 'assistant'}]