This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'First line drug for prophylaxis of pneumocystosis is \nSelect and explain. \nA. TMP-SMX, B. Dapsone, C. Pyrimethamine, D. Atovaquone', 'role': 'user'}, {'content': 'Answer: A \nExplanation: First line drug for prophylaxis of pneumocystosis is TMP-SMX (trimethoprim-sulfamethoxazole).Dapsone, Pyrimethamine, Atovaquone, Leucovorin, Pentamidine are second line drugs', 'role': 'assistant'}]