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 development disturbance in the enamel of mandibular first molar crown usually occurs between which of the following ages \nSelect and explain. \nA. 8 months prenatal to one year postnatal, B. Birth to 3 years postnatal, C. 3 years postnatal to 5 years postnatal, D. 6 years postnatal to 8 years postnatal', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]