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': 'Non arcon instruments gained considerable popularity in complete denture prosthodontics because upper and lower members are \nSelect and explain. \nA. Loosely attached, B. Rigidly attached, C. Medially attached, D. Inferiorly attached', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]