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': 'Which material is not used for construction of conical pontic \nSelect and explain. \nA. All metal, B. PFM, C. All ceramic, D. Resin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]