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': 'Which of the following is the most common cause of late neurological deterioration in a case of cerebrovascular accident : \nSelect and explain. \nA. Rebleeding, B. Vasospasm, C. Embolism, D. Hydrocephalus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Vasospasm): Vasospasnt: Narrowing of the aeries at the base of the brain following SAH occurs regularly. This vasospasm causes symptomatic ischemia and infarction in approximately 30% of patients and is the major cause of delayed morbidity or death. Sign of ischemia appear 4 to 14 days after the haemorrhage, most frequently at about 7 days - Harrisons 16th/ 2309 Four major causes of delayed neurological deficit Rerupture Hydrocephalus Vasospasm Hyponatremia', 'role': 'assistant'}]