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 Propagated epidemic is following Except \nSelect and explain. \nA. Secondary waves are absent, B. Spreads from person to person, C. The speed of spread depends upon Herd immunity, D. Shows gradual rise and fall over long period of me', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A propagated epidemic is most often infectious origin and results from person to person transmission of an infectious agent.The e[idemic usually shows a gradual rise and tails off over a much longer period of time.The speed of spread depends upon herd immunity, oppounities for contact and secondary atttack rate.Park 23e pg: 65', 'role': 'assistant'}]