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: Physiology
Thrombopoietin is produced by 
Select and explain. 
A. Monocytes, B. Liver, C. Megakaryocyte, D. Megakaryoblast
B: Liver
Answer: B: Liver 
Explanation: None