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': 'Berkesonian bias is due to: \nSelect and explain. \nA. Presence of confounding factors in both cases and controls, B. Questioning the cases more thoroughly as compared to controls, C. Different rates of admission to hospital due to different diseases, D. Better recall by the cases as compared to controls', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Different rates of admission to hospital due to different diseases', 'role': 'assistant'}]