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': 'Characteristic feature of agonist is - \nSelect and explain. \nA. Has affinity only, B. Has affinity as well as intrinsic activity, C. Has intrinsic activity only, D. Neither has affinity nor activity', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Has affinity as well as intrinsic activity", 'role': 'assistant'}]