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': 'Prefabricated pontics are commercially available as: \nSelect and explain. \nA. Metal pontics., B. Ceramic pontics., C. Porcelain pontics., D. Any of the above.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]