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': 'Study of molecular structure is done \nSelect and explain. \nA. Electron microscopy, B. Ion exchange chromatography, C. X-ray crystallography, D. Agarose gel electrophoresis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c. X-ray crystallography', 'role': 'assistant'}]