Which of the Following Is Not a Strategy for the Synthesis

Which of the following is not a strategy for the synthesis of polypeptides?

A) Protect the a-amino group of the amino acid aa1 to reduce its nucleophilicity so that the group does not participate in nucleophilic addition to the carboxyl group of either aa1 or aa2.
B) Cleave the polypeptide at specific peptide bonds, determine the sequence of each fragment, and then match overlapping fragments to arrive at the sequence of the polypeptide.
C) Activate the a-carboxyl group of the amino acid aa1 so that the group is susceptible to nucleophilic attack by the a-amino group of aa2.
D) Protect the a-carboxyl group of the amino acid aa2 so that the amino acid is not susceptible to nucleophilic attack by the a-amino group of another molecule of aa2.