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': 'Dubin Johnson syndrome characteristically makes the liver: \nSelect and explain. \nA. Black, B. Blue, C. Red, D. White', 'role': 'user'}, {'content': 'Answer: A \nExplanation: This rare\u202fautosomal recessive\u202fcondition, characterized by\u202fconjugated hyperbilirubinemia,\u202fwith\u202fnormal liver transaminases,\u202fa unique pattern of urinary excretion of heme metabolites (coproporphyrin) and the deposition of a\u202fpigment, that gives liver a characteristic\u202fblack color.', 'role': 'assistant'}]