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': 'Method (s) to determine protein structure is/are \nSelect and explain. \nA. X-Ray Crystallography, B. NMR Spectroscopy, C. Infrared spectroscopy, D. All of these', 'role': 'user'}, {'content': 'Answer: D \nExplanation: X-ray crystallography (X-ray diffraction)\nUV light spectroscopy and infra-red spectroscopy\nNuclear magnetic resonance (NMR) spectroscopy\nPolychromatic X-ray crystallography (Laue diffraction) \xa0\nOptical rotatory dispersion\nCircular dichroism\nComputer-based modelling\nMass spectrometry', 'role': 'assistant'}]