This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'An essential amino acid in man is \nSelect and explain. \nA. Aspartate, B. Tyrosine, C. Methionine, D. Serine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Isoleucine, Leucine, Threonine, Lysine, Methionine, Phenylalanine, Tryptophan, and Valine are essential amino acids.\nReference: Vasudevan 7th\xa0 ed, pg 27', 'role': 'assistant'}]