This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluid, Electrolyte and Nutrition, Subject name: Surgery
[{'content': 'Massive blood transfusion is defined as: \nSelect and explain. \nA. Whole blood volume in 24 hours, B. Half blood volume in 24 hours, C. 40% blood volume in 24 hours, D. 60% blood volume in 24 hours', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Massive transfusion is defined, in adults, as replacement of whole blood volume in 24 hours or >50% of blood volume in 4 hours.', 'role': 'assistant'}]