The correct answer is option (d). dehydration of proteins.
In the given reaction, the product is the condensed product of two amino acids present as the reactants. the reaction result in the formation of a diaminoacid molecule and water.
The reaction, in which the the water molecule is lost is known as the dehydration reaction. In this case, the carboxylic acid of the first amino acid reacts with the amino group of the second amino acid, and cause the release of the water molecule. Hence, this reaction is a dehydration of amino acids.