This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Hemoglobin binding protein is \nSelect and explain. \nA. Haptoglobin, B. Hemopexin, C. Albumin, D. Both Option 1 & 2', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Hemopexin- Binds to porphyrins, paicularly heme for heme recyclingHaptoglobin Binding, transpo of cell-free hemoglobin (Hemoglobin 1:1 binding)', 'role': 'assistant'}]