An essential amino acid in man is: (A) Aspartate, (B) Tyrosine, (C) Methionine, (D) Serine
Answer is C. Isoleucine, Leucine, Threonine, Lysine, Methionine, Phenylalanine, Tryptophan, and Valine are essential amino acids.
Reference: Vasudevan 7th  ed, pg 27