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': 'Which of the following is not an indication for bar clasp arm \nSelect and explain. \nA. When a small degree of undercut exists in cervical third of abutment tooth, B. On abutment teeth for tooth supported partial denture, C. Soft tissue undercuts, D. Distal extension bases', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The specific indications for using a bar clasp arm are\n\nWhen a small degree of undercut (0.01 inch) exists in the cervical third of the abutment tooth, which may be approached from a gingival direction.\nOn abutment teeth for tooth supported partial dentures or tooth supported modification areas .\nIn distal extension base situations.\nIn situations, where esthetics is a concern.', 'role': 'assistant'}]