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 NOT contraindicated about the use of β blockers in CHF \nSelect and explain. \nA. These should be started at very low dose and slowly titrated upwards, B. Carvedilol is most widely used β blocker, C. These are drug of choice in acute decompensated heart failure, D. These can reduce mortality in CHF patients', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Beta blockers are contraindicated in acute decompensated heart failure.', 'role': 'assistant'}]