This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
[{'content': 'Creatinine is synthesized from: \nSelect and explain. \nA. Glycine,arginine and methionine, B. Glycine and methionine, C. Ornithine and glycine, D. Thymine and ornithine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A Harper, 26lh ed, p. 268, Fig (31 - 6) & 25th ed, p. 354', 'role': 'assistant'}]