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': 'The usual incubation period of peusis is ? \nSelect and explain. \nA. 7-14 days, B. 3-5 days, C. 21-25 days, D. Less than 3 days', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 7-14 days Whooping cough (peussis) After an incubation period of about 1-2 weeks, the disease takes a protracted course comprising three stages-- the catarrhal, paroxysmal and convalescent - each lasting approximately two weeks.", 'role': 'assistant'}]