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: Pathology
[{'content': 'Which of the following is the most common cause of subacute endocarditis? \nSelect and explain. \nA. Staphylococcus aureus, B. Staphylococcus epidermidis, C. Streptococcus viridans, D. Streptococcus pyogenes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Intraoral Streptococcus viridans is the most common cause of subacute endocarditis.\xa0\nStaphylococcus\xa0aureus is the most common cause of acute endocarditis.', 'role': 'assistant'}]