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': "Valine is an essential amino acid since it cannot be synthesized by the body. Which of the following describes the side chain of valine? \nSelect and explain. \nA. Contains a sulfhydryl group, B. Contains a branched chain hydrocarbon, C. Contains an aromatic ring, D. Doesn't have a side chain", 'role': 'user'}, {'content': "Answer: B \nExplanation: Valine, along with isoleucine and leucine, are branched chain amino acids. Cysteine contains a sulfhydryl group. Phenylalanine contains an aromatic ring. Glycine doesn't have a side chain.", 'role': 'assistant'}]