This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardio thoracic surgery  , Subject name: Anatomy
[{'content': 'In Video assisted thoracoscooic surgery for better vision the space in the operative field is created by- \nSelect and explain. \nA. Self retaining retractor, B. Collapse of ipsilateral lung, C. Rib spacing, D. Co2 insufflations', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In contrast to most laparoscopic techniques, the working space for VATs is created not by adding an insuffalation gas but rather by removing air from the ipsilateral lung parenchyma causing collapse of the ipsilateral lung. Ref : Sabiston, 17/e p465', 'role': 'assistant'}]