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': 'What is true about confounding factor? \nSelect and explain. \nA. It is found equally between study and control groups, B. It itself is a risk factor for the disease, C. Confounding can be eliminated by selecting a small group, D. It is associated with either the exposure or the disease', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Confounding factor is defined as one which is associated with both exposure and disease and is distributed unequally in study and control groups. (refer pg no:72 park 23 rd edition)', 'role': 'assistant'}]