Which of the following is the most common cause of subacute endocarditis?
Intraoral Streptococcus viridans is the most common cause of subacute endocarditis. 
Staphylococcus aureus is the most common cause of acute endocarditis.
Staphylococcus aureus
Staphylococcus epidermidis
Streptococcus viridans
Streptococcus pyogenes