In the Z form of DNA the fundamental repeating unit is _________?

• A. Purine ‚Äö√Ñ√∂‚àö√ë‚àö¬® pyrimidine nucleotide
• B. Purine ‚Äö√Ñ√∂‚àö√ë‚àö¬® pyrimidine dinucleotide
• C. Purine ‚Äö√Ñ√∂‚àö√ë‚àö¬® pyrimidine tri-nucleotide
• D. Purine ‚Äö√Ñ√∂‚àö√ë‚àö¬® pyrimidine tetra-nucleotide