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: Pharmacology
[{'content': 'Maximum response a drug can produce regardless of its dose is known as: \nSelect and explain. \nA. Potency, B. Efficacy, C. Intrinsic activity, D. Agonist', 'role': 'user'}, {'content': 'Answer: B \nExplanation: It is the maximum effect produced by a drug.\nThe upper limit of DRC is the index of drug efficacy and refers to the maximal response that can be elicited by the drug, e.g. morphine produces a degree of analgesia not obtainable with any dose of aspirin-morphine is more efficacious than aspirin. Efficacy is a more decisive factor in the choice of a drug.', 'role': 'assistant'}]