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': 'Mouth preparation for removable cast partial denture include \nSelect and explain. \nA. Periodontal preparation only, B. Oral surgical preparation only, C. Abutment tooth preparation only, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]