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
In the maxilla, lack of stability was how many times more prevalent than lack of retention? 
Select and explain. 
A. 1.8 times, B. 4 times, C. 5.8 times, D. 7 times
D: 7 times
Answer: D: 7 times 
Explanation: In the maxilla, lack of stability - 7 times more prevalent than lack of retention.
In the mandible, lack of stability - 1.8 times more prevalent than lack of retention.