The correct option is C Tryptophan
Nonessential amino acids are made by the body, while essential amino acids cannot be made by the body and they must be obtained from the food we eat.
Isoleucine, leucine, threonine, lysine, methionine, phenylalanine, tryptophan, and valine are essential amino acids. The non-essential amino acids are alanine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, proline, serine and tyrosine.