This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Streptococci, Subject name: Microbiology
[{'content': 'Streptococcus pyogenes can be checked by which drug disk \nSelect and explain. \nA. Bacitracin, B. Polymycin, C. Optochin, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) BacitracinRef.: Microbiology by Ananthanarayan and Paniker 8th ed. /201, 206-07, 2012* The various species of Streptococcus can be checked by various drug disks which is indicated as whether it is sensitive or resistant to the drug.* S. pyogenes is bacitracin sensitive.* S. agalactiae is bacitracin resistant.* S. pneumoniae is inhibited by optochin.* S. viridans is not inhibited by optochin.', 'role': 'assistant'}]