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': 'Type of bone present on labial surface of anterior teeth \nSelect and explain. \nA. Cortical, B. Cancellous, C. Exophytic, D. Osteophytic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]