The Protein Data Bank, PDB, Is an International Database of 3D

The Protein Data Bank, PDB, is an international database of 3D molecular structures of biomolecules obtained by using _______________.
I. x-ray crystallography
II. light microscopy
III. scanning calorimetry
IV. NMR
V. electron microscopy

A) I, II, and III
B) I, III, and V
C) III, IV and V
D) II, III, and V
E) I, IV and V