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': 'Antibiotic used to for sensitivity in identification of streptococcus pyogenes? \nSelect and explain. \nA. Bacitracin, B. Novobiocin, C. Penicillin, D. Optochin', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Bacitracin Senstivity to bacitracin is employed as a convenient method for differentiating str. pyogenes from other hemolytic streptococci (Maxted's observation).", 'role': 'assistant'}]