67. Which statement is FALSE for the structural features of nucleotides? (A) There are two types of bases, purines and pyrimidines. (B) The most common form of DNA in nature is B-form. (C) DNA is more stable than RNA. (D) An A-T base pair has two H-bonds, and a G-C base pair has three H-bonds. (E) Cytosine, uracil, and thymine belong to purines； adenine and guanine belong to pyrimidines.