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': 'Smooth surface caries refers to \nSelect and explain. \nA. Facial and lingual surfaces, B. Occlusal pits and grooves, C. Mesial and distal surfaces, D. Both 1 and 3', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Smooth surface caries occurs on any of the axial (facial, lingual, mesial, and distal) tooth surfaces but not the occlusal.', 'role': 'assistant'}]