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': 'A person presents wth pneumonia. His sputum was sent for culture. The bacterium obtained was gram positive cocci in chains and alpha hemolytic colonies on sheep agar. Which of the following will help in confirming the diagnosis - \nSelect and explain. \nA. Novobiocin, B. Optochin, C. Bacitracin, D. Oxacillin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]