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': 'Most common infection causing OPSI after splenectomy \nSelect and explain. \nA. Streptococcus pneumonie, B. N. Meningitidis, C. E. Coli, D. Salmonella typhi', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]