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
A foreign body completely obstructing the right main bronchus causes - 
Select and explain. 
A. Decreased ventilation perfusion ratio, B. Increased ventilation in left lung, C. Perfusion doubles in right lung, D. Increased VF ratio in right lung
A: Decreased ventilation perfusion ratio
Answer: A: Decreased ventilation perfusion ratio 
Explanation: None