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': "Leon William's classification given an idea about \nSelect and explain. \nA. Number of teeth and size of the arch, B. Residual alveolar ridge, C. Form of tooth and face, D. Colour of artificial teeth", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]