X-Ray Crystallography Revealed Several Important Features of the Shape of DNA

Multiple Choice

X-ray crystallography revealed several important features of the shape of DNA. Which one of the following facts about DNA was NOT revealed by X-ray crystallography?

A) The shape of the molecule is helical.
B) The amount of purine bases equals the amount of pyrimidine bases.
C) The molecule has a constant diameter.
D) The phosphate groups are located on the outside.
E) All of these were revealed by X-ray crystallography.