This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycine Metabolism Detail, Subject name: Biochemistry
[{'content': 'N Methyl Glycine is known as: \nSelect and explain. \nA. Betaine, B. Sarcosine, C. Carnosine, D. Ergothionine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sarcosine/ N-methylglycine = intermediate and by-product in Glycine synthesis and degradation * Ergothionine is a thiourea derivative of Histidine, containing a sulfur atom on the imidazole ring * Betaine is N,N,N-Trimethylglycine, present in beet sugar. * Carnosine (Beta-Alanyl-L-Histidine), has Imidazole ring like Histidine, is a dipeptide molecule, made up of Beta-Alanine and Histidine. It is present in muscle and brain tissues.', 'role': 'assistant'}]