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: Physiology
The pressure between the layers of the pleura is negative due to the following reasons: 
Select and explain. 
A. The thoracic wall and lungs recoil in opposite directions, B. Intra pulmonary pressure is negative, C. Trans pulmonary pressure is negative, D. The surfactant prevents the pulmonary collapse
A: The thoracic wall and lungs recoil in opposite directions
Answer: A: The thoracic wall and lungs recoil in opposite directions 
Explanation: The tendency of the lungs and thoracic wall to recoil in the opposite direction expands the intrapleural space and creates negative pressure i.e. below the atmospheric pressure in between the two layers of pleura. Ref: Fundamentals of Respiratory Physiology By A. S. Chakrabay, Chakrabay, 2007, Page 33