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
[{'content': 'Which is an allosteric protein: \nSelect and explain. \nA. Transferrin, B. Ceruloplasmin, C. Phosphofructokinase, D. Haemoglobin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Hemoglobin', 'role': 'assistant'}]