This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pharmacology, Subject name: Pharmacology
[{'content': 'Antagonism between acetylCholine and atropine is? \nSelect and explain. \nA. Competitive antagonism, B. physiological antagonism, C. Noncompetitive antagonism, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Competitive antagonism (equilibrium type) -The antagonist is chemically similar to the agonist, competes with it and binds to the same site to the exclusion of the agonist molecules. Because the antagonist has affinity but no intrinsic activity no response is produced and the log DRC (dose-response curve) shifted to the right. Eg; Ach- atropine, morphine- naloxone Ref:KD Tripathi pharmacology 7th edition (page.no: 58)', 'role': 'assistant'}]