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': 'The association between disease & risk factor in a case control study is studied by- \nSelect and explain. \nA. Relative role, B. Attributable role, C. Population attributable role, D. Odds ratio', 'role': 'user'}, {'content': 'Answer: D \nExplanation: .<p>from a case control study we can derive what is known as odds ratio,which is measure of the strength of association between risk factor and outcome.</p><p>ref:park&;s textbook of preventive and social medicine,22 nd edition ,pg no 70</p>', 'role': 'assistant'}]