This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
[{'content': 'Antegrade peristalsis is due to \nSelect and explain. \nA. Serotonin, B. Ach, C. Substance P, D. VIP', 'role': 'user'}, {'content': 'Answer: D \nExplanation: * Peristalsis can be defined as a motor pattern of the gut organ musculature that can propel content into the anal (antegrade peristalsis) or oral (retrograde peristalsis) direction * Impulses travelling orad activate ascending contraction * Neurotransmitters here are acetylcholine, substance P, and neurokinin A. * Impulses travelling caudad activate descending relaxation * Neurotransmitters here are VIP, NO, and PACAP (pituitary adenylyl cyclase activating polypeptide). Ref:- Physiology of the Gastrointestinal Tract Sixth Edition; pg num:- 368', 'role': 'assistant'}]