This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': "Case control study - estimate - \nSelect and explain. \nA. Only odd's ratio, B. Odds ratio and attributable risk, C. Relative risk, attributable risk, population attributable risk, D. Incidence, Relative risk, and attributable risk", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]