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': 'Earliest phenotypic manifestation of Idiopathic hereditary hemochromatosis is - \nSelect and explain. \nA. Post prandial increase in serum iron concentration, B. Elevated serum ferritin level, C. Slate grey pigmentation of skin, D. Increased transferrin saturation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]