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 transport of CO is diffusion limited because 
Select and explain. 
A. Binds avidly with Hb, B. Partial pressure of CO is less, C. CO is less absorbed in water, D. Alveolar membrane is less permeable
A: Binds avidly with Hb
Answer: A: Binds avidly with Hb 
Explanation: None