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': 'Tissue displacement commonly needed to obtain \nSelect and explain. \nA. Adequate access to prepared tooth, B. To expose all necessary surfaces, both prepared and not prepared, C. Both of the above, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]