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
Rough, poorly polished areas of pontics may cause 
Select and explain. 
A. Halitosis, B. Discomfort, C. Chronic inflammation of the ridge tissue, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None