Which of the following features of the Watson-Crick model for DNA is incorrect?

• A. Two long polynucleotide chains are coiled around a central axis.
• B. The two chains are antiparallel.
• C. The nitrogenous bases of opposite chains are paired as the result of the formation of covalent bonds.
• D. In DNA, A always pairs with T and G always pairs with C.

Answer: (C)