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: Anatomy
[{'content': 'Platycephaly is: \nSelect and explain. \nA. Premature closure of unilateral occipitoparietal suture, B. Premature closure of bilateral coronal suture, C. Flat skull, D. Premature closure of unilateral coronal suture', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]