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
Causative organism of late prosthetic valve endocarditis is - 
Select and explain. 
A. Streptococcus viridans, B. Proteus mirabilis, C. Beta hemolytic streptococci, D. Staphylococci
A: Streptococcus viridans
Answer: A: Streptococcus viridans 
Explanation: None