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
A patient with parkinsonism suddenly presented with trembling, dizziness and upward reeling of eyes. It may be due to - 
Select and explain. 
A. Oculygyric crisis, B. Cholinergic crisis, C. Cerebrellar infarct, D. Cerebral infarct
A: Oculygyric crisis
Answer: A: Oculygyric crisis 
Explanation: None