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': 'Which of the following is second generation 3 blocker? \nSelect and explain. \nA. Propronolol, B. Timolol, C. Nodalol, D. Atenolol', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Atenolol", 'role': 'assistant'}]