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
Wedging in the interproximal areas in case of recession is called 
Select and explain. 
A. Piggy back, B. Tie back, C. Tie through, D. None of the above
A: Piggy back
Answer: A: Piggy back 
Explanation: None