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: Pathology
[{'content': 'Blood smear is best seen at pH of - \nSelect and explain. \nA. 7.2, B. 6.8, C. 6.6, D. 7', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]