This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'The organism that most commonly causes infective endocarditis is \nSelect and explain. \nA. Streptococcus mitis, B. Streptococcus viridians, C. Staphylococcus aureus, D. Staphylococcus pyogens', 'role': 'user'}, {'content': "Answer: B \nExplanation: Streptococcus sanguis is most common species in Viridans streptococcus to cause infective endocarditisReference: Jawetz, Melnick, & Adelberg's Medical Microbiology; 27th edition", 'role': 'assistant'}]