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': 'Molar-incisor hypoplasia in primary teeth at the occlusal level is due to developmental defect occurring during? \nSelect and explain. \nA. Birth to 12 months, B. 4th month intra-uterine to birth, C. 22 months to 26 months, D. 24 months to 48 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]