Three dna bases exist primarily as the keto tautomer because more hydrogen bonding interactions are possible in this form. however, it was originally thought that the bases existed as the enol tautomers because they appear to be more traditionally aromatic in this form. a. draw the aromatic enol tautomer of cytosine. b. draw the aromatic enol tautomer of guanine. c. draw the aromatic enol tautomer of thymine.