This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Anatomy
[{'content': 'After 72 hours of Myocardial infarction, the predominant cells are \nSelect and explain. \nA. Mast cells, B. Macrophages, C. Lymphocytes, D. Leukocytes', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]