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 patient with parkinsonism suddenly presented with trembling, dizziness and upward reeling of eyes. It may be due to - \nSelect and explain. \nA. Oculygyric crisis, B. Cholinergic crisis, C. Cerebrellar infarct, D. Cerebral infarct', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]