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': 'Intravenous PA is indicated in ischemic stroke within how many hours of onset of disease process \nSelect and explain. \nA. 1 hour, B. 3 hours, C. 6 hours, D. 12 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer- B. 3 hoursThe National Institute of Neurological Disorders and Stroke (NINDS) recombinant tPA (PA) Stroke Study showed a clear benefit for IV PA in selected patients with acute stroke.The NINDS study used IV PA (0.9 mg/kg to a 90-mg max; l0% as a bolus, then the remainder over 60 minutes) versus placebo in patients with ischemic stroke within 3 hours of onset.', 'role': 'assistant'}]