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
All of the following are used for gradation of coma in Glasgow coma scale except: 
Select and explain. 
A. Eye opening ,, B. Motor response, C. Verbal response, D. Bladder function
D: Bladder function
Answer: D: Bladder function 
Explanation: bladder dysfunction