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': 'True about point source epidemic is? \nSelect and explain. \nA. Occurs in more than 1 incubation period, B. Occurs in one incubation period, C. The exposure is continuous, D. Epidemic curve falls very slowly', 'role': 'user'}, {'content': "Answer: B \nExplanation: Common source single exposure epidemics is also known as point source epidemic. The exposure to the disease agent is brief and essentially simultaneous, the resultant cases all develop within one incubation period of the disease. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 72", 'role': 'assistant'}]