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: Anaesthesia
Which of these is most commonly used as pre-anesthetic medication? 
Select and explain. 
A. Atropine, B. Promethazine, C. Scopolamine, D. Glycopyrrolate
D: Glycopyrrolate
Answer: D: Glycopyrrolate 
Explanation: Ans: D. Glycopyrrolate(Ref: Miller 7/e p293; KDT 366, 117)Glycopyrrolate is most commonly used as pre-anesthetic medication.An anlicholinergic drug used for reducing secretions in the mouth, throat, airway, and stomach before surgery.Used before and during surgery to block ceain reflexes and to protect against ceain side effects of some medicines.