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': "Culture medium used for streptococcus pneumoniae \nSelect and explain. \nA. Human blood agar, B. Sheep blood agar, C. MacConkey's agar, D. Deoxycholate agar", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sheep blood agar', 'role': 'assistant'}]