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': 'In elderly patients distance between major and minor \napical foramina is \nSelect and explain. \nA. 1.5-2 mm, B. 0.75-1 mm, C. 0.2-0.5mm, D. 0-0.2 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]