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
Which of the following  pontic design is non-mucosal type? 
Select and explain. 
A. Ridge-lap, B. Modified ridge-lap, C. Sanitary, D. All of the above
C: Sanitary
Answer: C: Sanitary 
Explanation: None