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: Medicine
[{'content': 'Lallo, aged 54 years, who is a known diabetic patient develops cirrlosis. There is associated skin hyperpigmentation and restrictive cardioncyopathy which of the following is the best initial test to diagnose this case. \nSelect and explain. \nA. Total iron binding capacity, B. Serum ferritin, C. Serum copper, D. Serum ceruloplasmin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]