This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
[{'content': 'Drug of choice for pneumocystis carinii is \nSelect and explain. \nA. Doxycycline, B. Cotrimoxazole, C. Tetracycline, D. Dapsone', 'role': 'user'}, {'content': "Answer: B \nExplanation: The treatment of choice for PCP is trimethoprim-sulfamethoxazole (TMP-SMX), given either IV or PO for 14-21 days .TMP-SMX, which interferes with the organism's folate metabolism, is at least as effective as alternative agents and is better tolerated. Ref Harrison 19th edition pg 1019 Davidson edition23rd pg 587", 'role': 'assistant'}]