The right answer is a water molecule.
The bond is the result of the reaction between the carboxylic acid function COOH of the first amino acid and the NH 2 amine function of the second, with as a by-product a water molecule H2O.
The peptide bond is fundamental in the formation of peptides, polypeptides, and proteins. After the formation of the peptide bond, one end carries a free amino group - the N- or amino-terminal end, and the other end of a carboxyl - C- or carboxyl-terminus group.
