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: Medicine
[{'content': 'A 53 year old male, consumes alcohol in heavy dose for a long time, with documented evidence of vitamin B 6 deficiency, presented with pigmented rash of sun-exposed areas, bright red tongue, diarrhea, apathy, memory loss and disorientation. What could be the cause for these features? \nSelect and explain. \nA. Niacin deficiency, B. Riboflavin deficiency, C. Folate deficiency, D. Thiamine deficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The clinical features are suggestive of niacin deficiency. Alcoholism, vitamin B6 deficiency, riboflavin deficiency and tryptophan deficiency are the contributing factors for niacin deficiency. Ref:Harrisons Principles of Internal Medicine, 18th Edition, Page 594', 'role': 'assistant'}]