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': 'To notify a slide as AFB negative minimum how many fields should be checked? ? \nSelect and explain. \nA. 20, B. 100, C. 50, D. 200', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is `b' i.e., 100", 'role': 'assistant'}]