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 45-year-old man presents with history of frequent falls. He has difficulty in looking down also. What is the most probable diagnosis : \nSelect and explain. \nA. Normal pressure hydrocephalus, B. Parkinson's disease, C. Alzheimer's disease, D. Progressive supranuclear palsy", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Answer is D (Progressive supranuclear palsy):', 'role': 'assistant'}]