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
Subacute bacterial endocarditis is caused by 
Select and explain. 
A. Streptococcus viridans, B. Haemolytic streptococci, C. Staphylococcus aureus, D. Nisseria
A: Streptococcus viridans
Answer: A: Streptococcus viridans 
Explanation: None