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: Dental
[{'content': 'A chest physician observed that the distribution of forced expiratory volume (FEV) in 300 smokers had a median value of 2.5 litres with the first and third quartiles being 1.5 and 4.5 litres respectively. Based on this data, how many persons in the sample are expected to have a FEV between 1.5 and 4.5 litres? \nSelect and explain. \nA. 7.5, B. 150, C. 225, D. 300', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]