The correct answer is (c) Amino acid.
Amino acids are the building blocks of proteins. They are organic compounds that contain an amino group (-NH2), a carboxyl group (-COOH), and a side chain (R group). There are 20 different types of amino acids, which are linked together by peptide bonds to form proteins.
Iodic acid (HIO3) is a strong acid that is used in the production of other chemicals, such as iodine and potassium iodide. Formic acid (HCOOH) is a weak acid that is found in ants and bee stings. Nitrous acid (HNO2) is a weak acid that is used in the production of other chemicals, such as nitric acid and nitrous oxide.
Iodic acid, formic acid, and nitrous acid are not used to build proteins.