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
Ventilation perfusion ratio is maximum at : 
Select and explain. 
A. Apex of lung, B. Base of lung, C. Posterior lobe of lung, D. Middle of the lung
A: Apex of lung
Answer: A: Apex of lung 
Explanation: A i.e. Apex of lung