This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'In a normal individual erythropoiesis is completeed in how many days \nSelect and explain. \nA. 3, B. 7, C. 14, D. 20', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Erythropoiesis takes 7 days to complete in bone marrow', 'role': 'assistant'}]