All Are Important Functional Groups Participating in H-Bond Formation EXCEPT

Multiple Choice

All are important functional groups participating in H-bond formation EXCEPT:

A) amino group of the cytosine, adenine, and guanine.
B) the ring nitrogens at position 3 of pyrimidines and 1 of purines.
C) the electronegative oxygen atoms.
D) the electron density in the double bonds of the bases.
E) the carbonyl group at position 4 of uracil and thymine, position 2 of cytosine, and position 6 of guanine.