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': 'ABE (Acute Bacterial Endocarditis) is most commonly caused by: \nSelect and explain. \nA. Staph. aureus, B. Str. Viridans, C. Str. hemolyticus, D. Esch. Coli', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Staph. aureus', 'role': 'assistant'}]