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
Vertical section of ramus of mandible is done in which condition: 
Select and explain. 
A. Mandibular protrusion, B. Mandibular retrusion, C. Maxillary prognathism, D. Maxillary retrognathism
A: Mandibular protrusion
Answer: A: Mandibular protrusion 
Explanation: None