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
[{'content': 'Primary stress bearing area in mandibular edentulous \nridge is: \nSelect and explain. \nA. Buccal shelf, B. Crest of the ridge, C. Retromolar pad, D. Lingual flange', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]