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': 'Subacute combined degeneration of spinal cord is due to deficiency of \nSelect and explain. \nA. VitaminA, B. Vitamin C, C. Vitamin B12, D. Vitamin B3(Niacin)', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Vitamin B12", 'role': 'assistant'}]