Answer:
The correct answer is option D, that is, 27.
Explanation:
27 three-nucleotide codons would be possible when polynucleotide phosphorylase is supplemented to a solution of GTP, ATP, and UTP. As there are three nucleotides available, that is, guanine, adenine, and uracil and each codon comprise three nucleotides, thus, there would be a probability of (3)^3 codons, that is, 27.