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': 'A chronic alcoholic was complaining of loss of appetite and pain in lower legs. On examination his gate was ataxia. He is suffering from deficiency of \nSelect and explain. \nA. Niacin, B. Riboflavin, C. Thiamine, D. Folate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]