Identify neutral amino acid from following list represented by three letter symbols.

Step-by-step solution

To identify the neutral amino acid, consider the side chain properties of each option. Tryptophan (Trp) has an aromatic indole ring side chain that remains neutral at physiological pH. Arginine (Arg) contains a guanidinium group that is protonated and positively charged, while lysine (Lys) has a primary amino group that also carries a positive charge. Glutamic acid (Glu) features an additional carboxyl group that is deprotonated and negatively charged. Tryptophan is therefore the neutral amino acid among these opti