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: Biochemistry
Chief regulator of systemic iron homeostasis: 
Select and explain. 
A. Ferritin, B. Hepcidin, C. Haptoglobin, D. Transferrin
B: Hepcidin
Answer: B: Hepcidin 
Explanation: None