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 radiograph of 4-year-old child reveals no evidence\nof calcification of mandibular second pre molar.\nThis indicates \nSelect and explain. \nA. It is too early to make final prediction, B. The teeth may develop later, C. Primary second molar extracted to allow mesial drifting of permanent first molar, D. The child may never develop premolars', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]