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': "All of the following statements regarding case control and coho studies are true, Except - \nSelect and explain. \nA. Cohos are chosen based on history of `Exposure', B. Coho studies require longer time frame than case control studies, C. Coho studies are suitable to investigate 'rare' disease, D. Coho studies yield information about more than one disease", 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Coho studies are suitable to investigate 'rare' disease o Coho studies are inappropriate when the disease or exposure under investigation is rare.", 'role': 'assistant'}]