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': 'Most common organism causing meningitis in patients with CSF leak - \nSelect and explain. \nA. Pneumococcus, B. H. influenzae, C. Staphylococcus, D. E.coli', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]