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
To check objective pain response, which is best used method 
Select and explain. 
A. Facial pain scale, B. Knee jerk reflex, C. H - Reflex, D. R III Reflex
A: Facial pain scale
Answer: A: Facial pain scale 
Explanation: None