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
In a normal individual erythropoiesis is completeed in how many days 
Select and explain. 
A. 3, B. 7, C. 14, D. 20
B: 7
Answer: B: 7 
Explanation: Erythropoiesis takes 7 days to complete in bone marrow