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': "What is the gold standard investigation for Wilson's disease? \nSelect and explain. \nA. Measurement of serum ceruloplasmin, B. 24 hour urinary copper excretion, C. Liver biopsy, D. Serum copper estimation", 'role': 'user'}, {'content': "Answer: C \nExplanation: Gold standard investigation for Wilson's disease is liver biopsy with quantitative copper assay.", 'role': 'assistant'}]