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': 'The crowns and roots of primary molar at their cervical portions are more \nSelect and explain. \nA. Slender mesiodistally, B. Slender anteroposteriorly, C. Bulkier mesiodistally, D. Bulkier anteroposteriorly', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]