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': 'Posterior palatal seal is recorded when the head is bent at: \nSelect and explain. \nA. 30°, B. 15°, C. 60°, D. 45°', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]