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': 'Which of the following is true about coho study? \nSelect and explain. \nA. Disease to risk factor study, B. Effect to cause study, C. Not associated with attributable risk, D. Associated with antecedent causation', 'role': 'user'}, {'content': "Answer: D \nExplanation: A coho study is a paicular form of longitudinal study that samples a coho (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as bih or graduation), performing a cross-section at intervals through time. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 83", 'role': 'assistant'}]