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: Surgery
[{'content': 'Abbe-Estlander flap is used in repair of: \nSelect and explain. \nA. Breast, B. Lip, C. Esophagus, D. None of the above', 'role': 'user'}, {'content': "Answer: B \nExplanation: The lip-switch (Abbe-Estlander) flap or a stair-step advancement technique can be used to repair defects of either the upper or lower lip. Microstomia is a potential complication with these types of lip reconstruction. Ref: Schwaz's principle of surgery 9th edition, chapter 18", 'role': 'assistant'}]