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': 'Relative risk can be calculated by: September 2008 \nSelect and explain. \nA. Incidence of disease amongst exposed/incidence of disease amongst non-exposed, B. Incidence of disease amongst non-exposed/ incidence of disease amongst exposed, C. Incidence of disease amongst exposed/total population of that area, D. Incidence of disease amongst non-exposed/total population of that area', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Incidence of disease amongst exposed/incidence of disease amongst non-exposed', 'role': 'assistant'}]