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 angle of convexity is: \nSelect and explain. \nA. SNA, B. ANB, C. NA- Pog, D. SNB', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]