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: Biochemistry
[{'content': "Deficiency of vitamin A causes the following except: \nSelect and explain. \nA. Night blindness, B. Corneal dryness, C. Bitot's spots, D. Myopia", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]