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
In Video assisted thoracoscooic surgery for better vision the space in the operative field is created by? 
Select and explain. 
A. Self retaining retractor, B. CO2 insufflations, C. Collapse of ipsilateral lung, D. Rib spacing
C: Collapse of ipsilateral lung
Answer: C: Collapse of ipsilateral lung 
Explanation: Ans is 'c' i.e. collapse of ipsilateral lung 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.