Which of the following does not provide evidence to support the conclusion that nitrogenous bases pair in specific combinations?
A. a purine-purine pair is too wide to account for the 2-nm diameter of the double helix.
B. The sugar-phosphate backbone is held together by phosphodiester bonds.
C. The X-ray data suggested that the double helix had a uniform diameter.
D. Whenever one strand of DNA has a C, the partner strand has a G.
E. A pyrimidine-pyrimidine pair is too narrow o account for the 2nm-diameter of the double helix.