Answer:
L Group
Step-by-step explanation:
Proteins are made up of amino acids, these amino acids determine the protein's functional groups, in the image I annexed you can observe that amino acids have an amino group (NH2), an acid group(COOH) and a R group, a lateral chain that varies depending on the amino acid, in the protein these amino acids are linked through a peptide bond leaving one side of the chain with an acid group and the other side with an amide chain, keeping the R groups as well.
I hope you find this information useful and interesting! Good luck!