This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Biochemistry
[{'content': 'A female on maize as staple diet Its diarrhea and lesion in the neck region It is deficiency of \nSelect and explain. \nA. Niacin, B. Zinc, C. thiamine, D. Riboflavin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ref : lippincott 6th ed', 'role': 'assistant'}]