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: Surgery
[{'content': 'A most common organism isolated in breast abscess \nSelect and explain. \nA. Streptococcus, B. Staphylococcus aureus, C. Klebsiella, D. E coli', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common organism\xa0 responsible is staphylococcus aureus.\nIn lactating mothers causative organisms spread from nasopharynx of the infant.', 'role': 'assistant'}]