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': 'Generalised edema can be produced by deficiency of- \nSelect and explain. \nA. Vit. A, B. Thiamine, C. Vit. D, D. Folic acid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]