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
[{'content': 'Crystal violet blood agar is used for which bacteria? \nSelect and explain. \nA. Corynebacterium diphtheriae, B. Staph aureus, C. b-hemolytic streptococcus, D. Meningococcus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: b-hemolytic streptococcus', 'role': 'assistant'}]