This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
At the end of normal expiration 
Select and explain. 
A. The outward recoil tendency of the chest, B. The volume inside the lung is expiratory reserve volume, C. The chest wall has a tendency to move inwards, D. Alveolar pressure is usually negative
A: The outward recoil tendency of the chest
Answer: A: The outward recoil tendency of the chest 
Explanation: The outward recoil tendency of the chest for inspirationRef: Ganong&;s Review of Medical Physiology; 24th edition; page no: 629