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 best stimulator of respiratory centre is: 
Select and explain. 
A. Decrease in arterial carbon dioxide level, B. Increase in arterial carbon dioxide level, C. Increase in arterial oxygen level, D. None of the above
B: Increase in arterial carbon dioxide level
Answer: B: Increase in arterial carbon dioxide level 
Explanation: None