The correct response for what would most likely occur at letter D, as the mRNA strand moves along the ribosome complex, is:
B: tRNA molecules carrying amino acids start aligning with the mRNA codons.
During translation, tRNA molecules bring specific amino acids to the ribosome based on the codons of the mRNA strand. Each tRNA has an anticodon that complements the mRNA codon, allowing the correct amino acid to be added to the growing polypeptide chain. Responses A, C, and D do not accurately describe the process occurring during translation at this stage.