The correct option is A Proteins
Proteins are large-sized polymeric macromolecules having one or more polypeptides (chains of amino acids). Amino acids are organic acids having a carboxylic group, )-COOH) and an amino group (−NH2), generally attached to the a-carbon next to the carboxylic group. Carboxylic group provides an acidic property to the amino acid while amino group gives it a basic property.