This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Principles of Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Which of the following set is termed as epidemiological triad: \nSelect and explain. \nA. Endemic, epidemic and outbreaks, B. Agent, host and environment, C. Incidence, prevalence and disease load, D. Agent, man and disease', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans (b) Agent, host and environmentRef : K. Park 23rd ed. / 33-34, Park 19th/ 30A broad concept of disease causation that synthesized the basic factors of agent, host and environment (see adjacent figure)This model--agent, host and environment-- has been in use for many years. It helped epidemiologists to focus on different classes of factors, especially with regards to infectious diseases.', 'role': 'assistant'}]