The correct answer is short amino acid, NAM, NAG, and some lipid proteins.
Murein, also called peptidoglycan refers to a polymer comprising amino acids and sugars, which forms a mesh-like layer external to the plasma membrane of the majority of bacteria, producing the cell wall.
The sugar constituent comprises alternative residues of beta-1-4 linked NAM (N-acetylmuramic acid) and NAG (N-acetylglucosamine).