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: Microbiology
[{'content': 'Microscopic examination of a pus sample shows a filamentous organism which is acid fast with 1% sulphuric acid. Which of the following organisms could it be? \nSelect and explain. \nA. Actinomyces israeli, B. Nocardia brasiliensis, C. Streptomyces somaliensis, D. Blastomyces dermatitidis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]