This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Incubation period of Diptheria is \nSelect and explain. \nA. 2 -6 days, B. 2 - 6 hours, C. 2 - 6 weeks, D. 2 - 6 months', 'role': 'user'}, {'content': "Answer: A \nExplanation: The incubation period in diphtheria is commonly 3-4 days. In some cases sho as a day. In carriers, the incubation period may be very prolonged. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 240", 'role': 'assistant'}]