Correct Answer: B
Explanation:
Amino acids containing a secondary amine group (the only proteinogenic amino acid of this type is proline) are sometimes named imino acids. An imino acid is any molecule that contains both imino (>C=NH) and carboxyl (-C(=O)-OH) functional groups. Imino acids are related to amino acids, which contain both amino (-NH2) and carboxyl (-COOH) functional groups, differing in the bonding to the nitrogen