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
Most potent antiemitic agent used in preoperative period 
Select and explain. 
A. Glycopyrolate, B. Hyoscine, C. Atropine, D. Metochlorpromide
D: Metochlorpromide
Answer: D: Metochlorpromide 
Explanation: D i.e. Metochlopromide Metochlopramide increases lower esophageal sphinter tone, speeds gastric emptying & lowers gastric fluid volume & decreases risk for aspiration pneumonia due to antiemetic effect