Identifying a biomolecule class from its building blocks and function is a core conceptual skill, and the description here points clearly to one group. A compound formed by esterification of the trihydroxy alcohol glycerol with three fatty acid molecules is a triglyceride, also called a triacylglycerol, which is the chemical form of fats and oils. Such triesters are nonpolar, hydrophobic, and store a large amount of energy per gram, serving as the body's concentrated long-term energy reserve, so they belong to the lipid class. Proteins are polymers of amino acids joined by peptide bonds, not esters of glycerol, so that option is wrong. Carbohydrates such as polysaccharides are polymers of monosaccharide sugars linked by glycosidic bonds, which does not describe a glycerol triester. Nucleic acids are polynucleotides built from sugar, phosphate, and bases, again unrelated to fatty acid esters. This matches the standard classification of biomolecules. As a plausibility check, hydrolysis of this molecule, as in saponification with alkali, regenerates glycerol and the salts of three fatty acids, confirming its ester nature and its membership in the lipid family rather than any other class.