This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Half-life of factor VIII \nSelect and explain. \nA. 2-4 hours, B. 8-12 hours, C. 6 minutest, D. 60 days', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Factor VIII (8) Dosage Calculated on the basis that 1 unit/kg of factor VIII leads to a rise in plasma factor VIII of approximately 2%. EXAMPLE: 50 units/kg will increase factor VIII level by ~100%. Doses are rounded UP to the nearest l size. The half-life of factor VIII is 8-12 hours. Refer also to RCH Clinical Practice Guideline Haemophilia.', 'role': 'assistant'}]