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': 'Fraction of CPK is an enzyme that is elevated in a myocardial infarct is: \nSelect and explain. \nA. MM fraction, B. MB fraction, C. BB fraction, D. Both MM and BB fraction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]