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': 'The cardinal features of Parkinson’s syndrome include \nSelect and explain. \nA. Constant fine tremor, B. Muscle atrophy, C. Pupillary constriction, D. Akinesia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]