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: Medicine
[{'content': 'In a patient with chronic congestive cardiac failure,all of the following drugs prolong survival, except \nSelect and explain. \nA. Metoprolol, B. Carvedilol, C. Enalapril, D. Digoxin', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]