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': 'The classic opportunistic infection in acquired immune deficiency syndrome is: \nSelect and explain. \nA. Apthous stomatitis, B. Tuberculosis, C. Pneumocystis carinii pneumonia, D. Herpetic gingivostomatitis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]