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: Unknown
[{'content': 'Which of the following organism is seen in a patient of left-sided endocarditis involving the mitral valve? \nSelect and explain. \nA. Staphylococcus aureus, B. Streptococcus viridans, C. Enterococci, D. pseudomonas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. BVegetations (arrows) due to viridans streptococcal endocarditis involving the mitral valve.', 'role': 'assistant'}]