Final answer:
The process described involving mRNA, 70S ribosome, peptidyl-tRNA complex, aminoacyl-tRNAs, and elongation factors is Translation elongation, which corresponds to option B.
Step-by-step explanation:
The scenario described involves the presence of mRNA, a 70S ribosome, a peptidyl-tRNA complex in the P site, aminoacyl-tRNAs, and a set of proteins known as elongation factors (EFs) that use GTP. Given these components, the process being described is Translation elongation, which is option B. During translation elongation, amino acids are sequentially added to a growing polypeptide chain as the ribosome moves along the mRNA template. Charged tRNAs enter the A site of the ribosome, the peptide chain is transferred from the tRNA in the P site to the newly arrived amino acid, and the ribosome translocates along the mRNA by one codon. This moves the empty tRNA into the E site and the peptidyl-tRNA into the P site, making room for the next aminoacyl-tRNA to bind to the A site.