This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'What is not true about point source epidemic? \nSelect and explain. \nA. Plateau phace, B. No secondary waves, C. Explosive epidemic, D. Only one peak', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .point source epidemics ,here the eriod of exposure is only brief,and simultaneous ,the resultant cases will develop within one incubation period of the disease.the curve has usually one peak.the epidemic curve rises and falls rapidly, with no secondary waves.and it tends to be explosive. ref:park&;s textbook,ed 22,pg no 62', 'role': 'assistant'}]