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
Primary stress bearing area in mandibular edentulous 
ridge is: 
Select and explain. 
A. Buccal shelf, B. Crest of the ridge, C. Retromolar pad, D. Lingual flange
A: Buccal shelf
Answer: A: Buccal shelf 
Explanation: None