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
What are the requirements of a pontic: 
Select and explain. 
A. Restore function., B. Permit effective oral hygiene., C. Preserve underlying residual mucosa., D. All of the above.
D: All of the above.
Answer: D: All of the above. 
Explanation: The requirements of a pontic are:  
• Restore function
• Provide esthetics and comfort
• Biologically acceptable
• Permit effective oral hygiene
• Preserve underlying residual mucosa