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
Study of molecular structure is done 
Select and explain. 
A. Electron microscopy, B. Ion exchange chromatography, C. X-ray crystallography, D. Agarose gel electrophoresis
C: X-ray crystallography
Answer: C: X-ray crystallography 
Explanation: Ans. c. X-ray crystallography