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': 'Golden hour in thrombolytic therapy for cerebral stroke- \nSelect and explain. \nA. 3 hrs, B. 6 hrs, C. 12 hrs, D. 24 hrs', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]