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': 'Wedging in the interproximal areas in case of recession is called \nSelect and explain. \nA. Piggy back, B. Tie back, C. Tie through, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]