3. In the Watson-Crick model for the DNA double helix (B form), the A-T and G-C base
pairs share which one of the following properties?
(A) The distance between the two glycosidic (base-sugar) bonds is the same in both
base pairs, within a few tenths of an angstrom.
(B) The molecular weights of the two base pairs are identical.
(C) The number of hydrogen bonds formed between the two bases of the base pair
is the same.
(D) The plane of neither base pair is perpendicular to the axis of the helix.
(E) The proton-binding groups in both base pairs are in their charged or ionized
form.