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
Which of the following is the most common cause of subacute endocarditis? 
Select and explain. 
A. Staphylococcus aureus, B. Staphylococcus epidermidis, C. Streptococcus viridans, D. Streptococcus pyogenes
C: Streptococcus viridans
Answer: C: Streptococcus viridans 
Explanation: Intraoral Streptococcus viridans is the most common cause of subacute endocarditis. 
Staphylococcus aureus is the most common cause of acute endocarditis.