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': 'During peristalsis which of the following is not involved? \nSelect and explain. \nA. NO, B. Substance P, C. Noradrenalin, D. VIP', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ach & Substance P are responsible for the proximal contracting segment of peristalsis NO & VIP are responsible for the distal Relaxation Ref: Ganong 25th ed/page 497', 'role': 'assistant'}]