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
Leon William's classification given an idea about 
Select and explain. 
A. Number of teeth and size of the arch, B. Residual alveolar ridge, C. Form of tooth and face, D. Colour of artificial teeth
C: Form of tooth and face
Answer: C: Form of tooth and face 
Explanation: None