Adehydration synthesis reaction is best described as a chemical reaction in which

A dehydration synthesis reaction is best described as a chemical reaction in which small reactants combines to form larger molecules with loss of water.

Explanation:

When small molecules acts as reactants to form larger compounds with the loss of water molecules, we called this kind of reaction a "synthesis reaction". These reactions are typicall in biological systemas, when monomers combines to form polymers. For example, two aminoacids reacting to form a dimer, constitutes a synthesis reaction.

your answer should be c) enjoy!