This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preoperative assessment and monitoring in anaesthesia, Subject name: Anaesthesia
Most potent antiemetic agent used in preoperative period 
Select and explain. 
A. Glycopyrolate, B. Hyoscine, C. Atropine, D. Metochlorpromide
B: Hyoscine
Answer: B: Hyoscine 
Explanation: the most potent anti-emetic used is hyoscine . the most commonly used anti-emetics are metochlopramide,ondensetron.