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': 'The substance present in the gall bladder stones or the kidney stones can be best identified by the following techniques: \nSelect and explain. \nA. Fluorescence spectroscopy, B. Electron microscopy, C. Nuclear magnetic resonance, D. X-ray diffraction', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Polarizing microscopy, X-ray diffraction and infrared spectroscopy are techniques for analysing renal and gall bladder stones.', 'role': 'assistant'}]