This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Opioids and Alcohols, Subject name: Pharmacology
[{'content': 'Morphine is used in the treatment of:- \nSelect and explain. \nA. Hypeension, B. Cardiac arrhythmias, C. Acute left ventricular failure, D. A-V block', 'role': 'user'}, {'content': 'Answer: C \nExplanation: These are used as analgesic agents. Visceral, dull and constant pain is relieved more effectively than inflammatory pain. Opioids are however contraindicated in biliary colic. Morphine (i.v.) is useful in myocardial infarction as well as in pulmonary edema due to acute left ventricular failure.', 'role': 'assistant'}]