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': 'Coho study is better than case control study in all ways except \nSelect and explain. \nA. Greater Comparability, B. Lesser time spent, C. Prospective analysis, D. Less Bias', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Coho study: Involves larger no of subjects Long follow up period needed involving delayed results Expensive Yields incidence rate relative risk as well attributable risk (refer pgno:79 park 23rd edition)', 'role': 'assistant'}]