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: Physiology
[{'content': "Normal adult person's blood contains: \nSelect and explain. \nA. 40% neutrophils, B. 30% lymphocytes, C. 20% eosinophils, D. 10% basophils", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]