This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'The normal total iron binding capacity is \nSelect and explain. \nA. 0.5-1 mg/Litre, B. 1.5-2.5 mg/Litre, C. 1.0-1.5 mg/Litre, D. 300-400 mg/dl', 'role': 'user'}, {'content': 'Answer: D \nExplanation: .', 'role': 'assistant'}]