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
Which of the following factor increases gastric motility? 
Select and explain. 
A. Acid in duodenum, B. Fatty food in stomach, C. Carbohydrate in stomach, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Fats, carbohydrates, and acid in the duodenum inhibit gastric acid and pepsin secretion and gastric motility neural and hormonal mechanisms. The messenger involved is probably peptide YY. CCK has also been implicated as an inhibitor of gastric emptying. Hyperosmolality of the duodenal contents is sensed by "duodenal osmoreceptors" that initiate a decrease in gastric emptying, which is probably neural in origin. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 27. Gastrointestinal Motility. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.